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tablecmds.c
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Magnus Hagander authoredMagnus Hagander authored
tablecmds.c 247.55 KiB
/*-------------------------------------------------------------------------
*
* tablecmds.c
* Commands for creating and altering table structures and settings
*
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/commands/tablecmds.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/reloptions.h"
#include "access/relscan.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_depend.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_inherits_fn.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_type.h"
#include "catalog/pg_type_fn.h"
#include "catalog/storage.h"
#include "catalog/toasting.h"
#include "commands/cluster.h"
#include "commands/comment.h"
#include "commands/defrem.h"
#include "commands/sequence.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
#include "commands/trigger.h"
#include "commands/typecmds.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "nodes/parsenodes.h"
#include "optimizer/clauses.h"
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "parser/parse_type.h"
#include "parser/parse_utilcmd.h"
#include "parser/parser.h"
#include "rewrite/rewriteDefine.h"
#include "rewrite/rewriteHandler.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "storage/lock.h"
#include "storage/smgr.h"
#include "utils/acl.h"
#include "utils/builtins.h"#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/relcache.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/tqual.h"
/*
* ON COMMIT action list
*/
typedef struct OnCommitItem
{
Oid relid; /* relid of relation */
OnCommitAction oncommit; /* what to do at end of xact */
/*
* If this entry was created during the current transaction,
* creating_subid is the ID of the creating subxact; if created in a prior
* transaction, creating_subid is zero. If deleted during the current
* transaction, deleting_subid is the ID of the deleting subxact; if no
* deletion request is pending, deleting_subid is zero.
*/
SubTransactionId creating_subid;
SubTransactionId deleting_subid;
} OnCommitItem;
static List *on_commits = NIL;
/*
* State information for ALTER TABLE
*
* The pending-work queue for an ALTER TABLE is a List of AlteredTableInfo
* structs, one for each table modified by the operation (the named table
* plus any child tables that are affected). We save lists of subcommands
* to apply to this table (possibly modified by parse transformation steps);
* these lists will be executed in Phase 2. If a Phase 3 step is needed,
* necessary information is stored in the constraints and newvals lists.
*
* Phase 2 is divided into multiple passes; subcommands are executed in
* a pass determined by subcommand type.
*/
#define AT_PASS_DROP 0 /* DROP (all flavors) */
#define AT_PASS_ALTER_TYPE 1 /* ALTER COLUMN TYPE */
#define AT_PASS_OLD_INDEX 2 /* re-add existing indexes */
#define AT_PASS_OLD_CONSTR 3 /* re-add existing constraints */
#define AT_PASS_COL_ATTRS 4 /* set other column attributes */
/* We could support a RENAME COLUMN pass here, but not currently used */
#define AT_PASS_ADD_COL 5 /* ADD COLUMN */
#define AT_PASS_ADD_INDEX 6 /* ADD indexes */
#define AT_PASS_ADD_CONSTR 7 /* ADD constraints, defaults */
#define AT_PASS_MISC 8 /* other stuff */
#define AT_NUM_PASSES 9
typedef struct AlteredTableInfo
{
/* Information saved before any work commences: */
Oid relid; /* Relation to work on */
char relkind; /* Its relkind */
TupleDesc oldDesc; /* Pre-modification tuple descriptor */
/* Information saved by Phase 1 for Phase 2: */
List *subcmds[AT_NUM_PASSES]; /* Lists of AlterTableCmd */
/* Information saved by Phases 1/2 for Phase 3: */
List *constraints; /* List of NewConstraint */
List *newvals; /* List of NewColumnValue */
bool new_notnull; /* T if we added new NOT NULL constraints */ bool new_changeoids; /* T if we added/dropped the OID column */
Oid newTableSpace; /* new tablespace; 0 means no change */
/* Objects to rebuild after completing ALTER TYPE operations */
List *changedConstraintOids; /* OIDs of constraints to rebuild */
List *changedConstraintDefs; /* string definitions of same */
List *changedIndexOids; /* OIDs of indexes to rebuild */
List *changedIndexDefs; /* string definitions of same */
} AlteredTableInfo;
/* Struct describing one new constraint to check in Phase 3 scan */
/* Note: new NOT NULL constraints are handled elsewhere */
typedef struct NewConstraint
{
char *name; /* Constraint name, or NULL if none */
ConstrType contype; /* CHECK or FOREIGN */
Oid refrelid; /* PK rel, if FOREIGN */
Oid refindid; /* OID of PK's index, if FOREIGN */
Oid conid; /* OID of pg_constraint entry, if FOREIGN */
Node *qual; /* Check expr or CONSTR_FOREIGN Constraint */
List *qualstate; /* Execution state for CHECK */
} NewConstraint;
/*
* Struct describing one new column value that needs to be computed during
* Phase 3 copy (this could be either a new column with a non-null default, or
* a column that we're changing the type of). Columns without such an entry
* are just copied from the old table during ATRewriteTable. Note that the
* expr is an expression over *old* table values.
*/
typedef struct NewColumnValue
{
AttrNumber attnum; /* which column */
Expr *expr; /* expression to compute */
ExprState *exprstate; /* execution state */
} NewColumnValue;
/*
* Error-reporting support for RemoveRelations
*/
struct dropmsgstrings
{
char kind;
int nonexistent_code;
const char *nonexistent_msg;
const char *skipping_msg;
const char *nota_msg;
const char *drophint_msg;
};
static const struct dropmsgstrings dropmsgstringarray[] = {
{RELKIND_RELATION,
ERRCODE_UNDEFINED_TABLE,
gettext_noop("table \"%s\" does not exist"),
gettext_noop("table \"%s\" does not exist, skipping"),
gettext_noop("\"%s\" is not a table"),
gettext_noop("Use DROP TABLE to remove a table.")},
{RELKIND_SEQUENCE,
ERRCODE_UNDEFINED_TABLE,
gettext_noop("sequence \"%s\" does not exist"),
gettext_noop("sequence \"%s\" does not exist, skipping"),
gettext_noop("\"%s\" is not a sequence"),
gettext_noop("Use DROP SEQUENCE to remove a sequence.")},
{RELKIND_VIEW,
ERRCODE_UNDEFINED_TABLE,
gettext_noop("view \"%s\" does not exist"),
gettext_noop("view \"%s\" does not exist, skipping"),
gettext_noop("\"%s\" is not a view"),
gettext_noop("Use DROP VIEW to remove a view.")},
{RELKIND_INDEX,
ERRCODE_UNDEFINED_OBJECT, gettext_noop("index \"%s\" does not exist"),
gettext_noop("index \"%s\" does not exist, skipping"),
gettext_noop("\"%s\" is not an index"),
gettext_noop("Use DROP INDEX to remove an index.")},
{RELKIND_COMPOSITE_TYPE,
ERRCODE_UNDEFINED_OBJECT,
gettext_noop("type \"%s\" does not exist"),
gettext_noop("type \"%s\" does not exist, skipping"),
gettext_noop("\"%s\" is not a type"),
gettext_noop("Use DROP TYPE to remove a type.")},
{'\0', 0, NULL, NULL, NULL, NULL}
};
static void truncate_check_rel(Relation rel);
static List *MergeAttributes(List *schema, List *supers, bool istemp,
List **supOids, List **supconstr, int *supOidCount);
static bool MergeCheckConstraint(List *constraints, char *name, Node *expr);
static bool change_varattnos_walker(Node *node, const AttrNumber *newattno);
static void MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel);
static void MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel);
static void StoreCatalogInheritance(Oid relationId, List *supers);
static void StoreCatalogInheritance1(Oid relationId, Oid parentOid,
int16 seqNumber, Relation inhRelation);
static int findAttrByName(const char *attributeName, List *schema);
static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
static void AlterIndexNamespaces(Relation classRel, Relation rel,
Oid oldNspOid, Oid newNspOid);
static void AlterSeqNamespaces(Relation classRel, Relation rel,
Oid oldNspOid, Oid newNspOid,
const char *newNspName, LOCKMODE lockmode);
static int transformColumnNameList(Oid relId, List *colList,
int16 *attnums, Oid *atttypids);
static int transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
List **attnamelist,
int16 *attnums, Oid *atttypids,
Oid *opclasses);
static Oid transformFkeyCheckAttrs(Relation pkrel,
int numattrs, int16 *attnums,
Oid *opclasses);
static void checkFkeyPermissions(Relation rel, int16 *attnums, int natts);
static void validateForeignKeyConstraint(Constraint *fkconstraint,
Relation rel, Relation pkrel,
Oid pkindOid, Oid constraintOid);
static void createForeignKeyTriggers(Relation rel, Constraint *fkconstraint,
Oid constraintOid, Oid indexOid);
static void ATController(Relation rel, List *cmds, bool recurse, LOCKMODE lockmode);
static void ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
bool recurse, bool recursing, LOCKMODE lockmode);
static void ATRewriteCatalogs(List **wqueue, LOCKMODE lockmode);
static void ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
AlterTableCmd *cmd, LOCKMODE lockmode);
static void ATRewriteTables(List **wqueue, LOCKMODE lockmode);
static void ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode);
static AlteredTableInfo *ATGetQueueEntry(List **wqueue, Relation rel);
static void ATSimplePermissions(Relation rel, bool allowView);
static void ATSimplePermissionsRelationOrIndex(Relation rel);
static void ATSimpleRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd, bool recurse, LOCKMODE lockmode);
static void ATOneLevelRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd, LOCKMODE lockmode);
static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
AlterTableCmd *cmd, LOCKMODE lockmode);
static void ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
ColumnDef *colDef, bool isOid, LOCKMODE lockmode);
static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid);
static void ATPrepAddOids(List **wqueue, Relation rel, bool recurse,
AlterTableCmd *cmd, LOCKMODE lockmode);
static void ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode);
static void ATExecSetNotNull(AlteredTableInfo *tab, Relation rel, const char *colName, LOCKMODE lockmode);
static void ATExecColumnDefault(Relation rel, const char *colName,
Node *newDefault, LOCKMODE lockmode);
static void ATPrepSetStatistics(Relation rel, const char *colName,
Node *newValue, LOCKMODE lockmode);
static void ATExecSetStatistics(Relation rel, const char *colName,
Node *newValue, LOCKMODE lockmode);
static void ATExecSetOptions(Relation rel, const char *colName,
Node *options, bool isReset, LOCKMODE lockmode);
static void ATExecSetStorage(Relation rel, const char *colName,
Node *newValue, LOCKMODE lockmode);
static void ATPrepDropColumn(Relation rel, bool recurse, AlterTableCmd *cmd);
static void ATExecDropColumn(List **wqueue, Relation rel, const char *colName,
DropBehavior behavior,
bool recurse, bool recursing,
bool missing_ok, LOCKMODE lockmode);
static void ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
IndexStmt *stmt, bool is_rebuild, LOCKMODE lockmode);
static void ATExecAddConstraint(List **wqueue,
AlteredTableInfo *tab, Relation rel,
Constraint *newConstraint, bool recurse, LOCKMODE lockmode);
static void ATAddCheckConstraint(List **wqueue,
AlteredTableInfo *tab, Relation rel,
Constraint *constr,
bool recurse, bool recursing, LOCKMODE lockmode);
static void ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
Constraint *fkconstraint, LOCKMODE lockmode);
static void ATExecDropConstraint(Relation rel, const char *constrName,
DropBehavior behavior,
bool recurse, bool recursing,
bool missing_ok, LOCKMODE lockmode);
static void ATPrepAlterColumnType(List **wqueue,
AlteredTableInfo *tab, Relation rel,
bool recurse, bool recursing,
AlterTableCmd *cmd, LOCKMODE lockmode);
static void ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
const char *colName, TypeName *typeName, LOCKMODE lockmode);
static void ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab, LOCKMODE lockmode);
static void ATPostAlterTypeParse(char *cmd, List **wqueue, LOCKMODE lockmode);
static void change_owner_recurse_to_sequences(Oid relationOid,
Oid newOwnerId, LOCKMODE lockmode);
static void ATExecClusterOn(Relation rel, const char *indexName, LOCKMODE lockmode);
static void ATExecDropCluster(Relation rel, LOCKMODE lockmode);
static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel,
char *tablespacename, LOCKMODE lockmode);
static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode);
static void ATExecSetRelOptions(Relation rel, List *defList, bool isReset, LOCKMODE lockmode);
static void ATExecEnableDisableTrigger(Relation rel, char *trigname,
char fires_when, bool skip_system, LOCKMODE lockmode);
static void ATExecEnableDisableRule(Relation rel, char *rulename,
char fires_when, LOCKMODE lockmode);
static void ATPrepAddInherit(Relation child_rel);
static void ATExecAddInherit(Relation child_rel, RangeVar *parent, LOCKMODE lockmode);
static void ATExecDropInherit(Relation rel, RangeVar *parent, LOCKMODE lockmode);
static void copy_relation_data(SMgrRelation rel, SMgrRelation dst,
ForkNumber forkNum, bool istemp);
static const char *storage_name(char c);
/* ----------------------------------------------------------------
* DefineRelation
* Creates a new relation.
*
* stmt carries parsetree information from an ordinary CREATE TABLE statement.
* The other arguments are used to extend the behavior for other cases:
* relkind: relkind to assign to the new relation
* ownerId: if not InvalidOid, use this as the new relation's owner.
*
* Note that permissions checks are done against current user regardless of
* ownerId. A nonzero ownerId is used when someone is creating a relation * "on behalf of" someone else, so we still want to see that the current user
* has permissions to do it.
*
* If successful, returns the OID of the new relation.
* ----------------------------------------------------------------
*/
Oid
DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId)
{
char relname[NAMEDATALEN];
Oid namespaceId;
List *schema = stmt->tableElts;
Oid relationId;
Oid tablespaceId;
Relation rel;
TupleDesc descriptor;
List *inheritOids;
List *old_constraints;
bool localHasOids;
int parentOidCount;
List *rawDefaults;
List *cookedDefaults;
Datum reloptions;
ListCell *listptr;
AttrNumber attnum;
static char *validnsps[] = HEAP_RELOPT_NAMESPACES;
Oid ofTypeId;
/*
* Truncate relname to appropriate length (probably a waste of time, as
* parser should have done this already).
*/
StrNCpy(relname, stmt->relation->relname, NAMEDATALEN);
/*
* Check consistency of arguments
*/
if (stmt->oncommit != ONCOMMIT_NOOP && !stmt->relation->istemp)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("ON COMMIT can only be used on temporary tables")));
/*
* Security check: disallow creating temp tables from security-restricted
* code. This is needed because calling code might not expect untrusted
* tables to appear in pg_temp at the front of its search path.
*/
if (stmt->relation->istemp && InSecurityRestrictedOperation())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("cannot create temporary table within security-restricted operation")));
/*
* Look up the namespace in which we are supposed to create the relation.
* Check we have permission to create there. Skip check if bootstrapping,
* since permissions machinery may not be working yet.
*/
namespaceId = RangeVarGetCreationNamespace(stmt->relation);
if (!IsBootstrapProcessingMode())
{
AclResult aclresult;
aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
get_namespace_name(namespaceId));
}
/*
* Select tablespace to use. If not specified, use default tablespace
* (which may in turn default to database's default).
*/
if (stmt->tablespacename)
{
tablespaceId = get_tablespace_oid(stmt->tablespacename, false);
}
else
{
tablespaceId = GetDefaultTablespace(stmt->relation->istemp);
/* note InvalidOid is OK in this case */
}
/* Check permissions except when using database's default */
if (OidIsValid(tablespaceId) && tablespaceId != MyDatabaseTableSpace)
{
AclResult aclresult;
aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_TABLESPACE,
get_tablespace_name(tablespaceId));
}
/* In all cases disallow placing user relations in pg_global */
if (tablespaceId == GLOBALTABLESPACE_OID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("only shared relations can be placed in pg_global tablespace")));
/* Identify user ID that will own the table */
if (!OidIsValid(ownerId))
ownerId = GetUserId();
/*
* Parse and validate reloptions, if any.
*/
reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
true, false);
(void) heap_reloptions(relkind, reloptions, true);
if (stmt->ofTypename)
ofTypeId = typenameTypeId(NULL, stmt->ofTypename, NULL);
else
ofTypeId = InvalidOid;
/*
* Look up inheritance ancestors and generate relation schema, including
* inherited attributes.
*/
schema = MergeAttributes(schema, stmt->inhRelations,
stmt->relation->istemp,
&inheritOids, &old_constraints, &parentOidCount);
/*
* Create a tuple descriptor from the relation schema. Note that this
* deals with column names, types, and NOT NULL constraints, but not
* default values or CHECK constraints; we handle those below.
*/
descriptor = BuildDescForRelation(schema);
localHasOids = interpretOidsOption(stmt->options);
descriptor->tdhasoid = (localHasOids || parentOidCount > 0);
/*
* Find columns with default values and prepare for insertion of the
* defaults. Pre-cooked (that is, inherited) defaults go into a list of * CookedConstraint structs that we'll pass to heap_create_with_catalog,
* while raw defaults go into a list of RawColumnDefault structs that will
* be processed by AddRelationNewConstraints. (We can't deal with raw
* expressions until we can do transformExpr.)
*
* We can set the atthasdef flags now in the tuple descriptor; this just
* saves StoreAttrDefault from having to do an immediate update of the
* pg_attribute rows.
*/
rawDefaults = NIL;
cookedDefaults = NIL;
attnum = 0;
foreach(listptr, schema)
{
ColumnDef *colDef = lfirst(listptr);
attnum++;
if (colDef->raw_default != NULL)
{
RawColumnDefault *rawEnt;
Assert(colDef->cooked_default == NULL);
rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
rawEnt->attnum = attnum;
rawEnt->raw_default = colDef->raw_default;
rawDefaults = lappend(rawDefaults, rawEnt);
descriptor->attrs[attnum - 1]->atthasdef = true;
}
else if (colDef->cooked_default != NULL)
{
CookedConstraint *cooked;
cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
cooked->contype = CONSTR_DEFAULT;
cooked->name = NULL;
cooked->attnum = attnum;
cooked->expr = colDef->cooked_default;
cooked->is_local = true; /* not used for defaults */
cooked->inhcount = 0; /* ditto */
cookedDefaults = lappend(cookedDefaults, cooked);
descriptor->attrs[attnum - 1]->atthasdef = true;
}
}
/*
* Create the relation. Inherited defaults and constraints are passed in
* for immediate handling --- since they don't need parsing, they can be
* stored immediately.
*/
relationId = heap_create_with_catalog(relname,
namespaceId,
tablespaceId,
InvalidOid,
InvalidOid,
ofTypeId,
ownerId,
descriptor,
list_concat(cookedDefaults,
old_constraints),
relkind,
false,
false,
localHasOids,
parentOidCount,
stmt->oncommit,
reloptions,
true, allowSystemTableMods,
stmt->if_not_exists);
/*
* If heap_create_with_catalog returns InvalidOid, it means that the user
* specified "IF NOT EXISTS" and the relation already exists. In that
* case we do nothing further.
*/
if (relationId == InvalidOid)
return InvalidOid;
/* Store inheritance information for new rel. */
StoreCatalogInheritance(relationId, inheritOids);
/*
* We must bump the command counter to make the newly-created relation
* tuple visible for opening.
*/
CommandCounterIncrement();
/*
* Open the new relation and acquire exclusive lock on it. This isn't
* really necessary for locking out other backends (since they can't see
* the new rel anyway until we commit), but it keeps the lock manager from
* complaining about deadlock risks.
*/
rel = relation_open(relationId, AccessExclusiveLock);
/*
* Now add any newly specified column default values and CHECK constraints
* to the new relation. These are passed to us in the form of raw
* parsetrees; we need to transform them to executable expression trees
* before they can be added. The most convenient way to do that is to
* apply the parser's transformExpr routine, but transformExpr doesn't
* work unless we have a pre-existing relation. So, the transformation has
* to be postponed to this final step of CREATE TABLE.
*/
if (rawDefaults || stmt->constraints)
AddRelationNewConstraints(rel, rawDefaults, stmt->constraints,
true, true);
/*
* Clean up. We keep lock on new relation (although it shouldn't be
* visible to anyone else anyway, until commit).
*/
relation_close(rel, NoLock);
return relationId;
}
/*
* Emit the right error or warning message for a "DROP" command issued on a
* non-existent relation
*/
static void
DropErrorMsgNonExistent(const char *relname, char rightkind, bool missing_ok)
{
const struct dropmsgstrings *rentry;
for (rentry = dropmsgstringarray; rentry->kind != '\0'; rentry++)
{
if (rentry->kind == rightkind)
{
if (!missing_ok)
{
ereport(ERROR,
(errcode(rentry->nonexistent_code),
errmsg(rentry->nonexistent_msg, relname)));
}
else {
ereport(NOTICE, (errmsg(rentry->skipping_msg, relname)));
break;
}
}
}
Assert(rentry->kind != '\0'); /* Should be impossible */
}
/*
* Emit the right error message for a "DROP" command issued on a
* relation of the wrong type
*/
static void
DropErrorMsgWrongType(const char *relname, char wrongkind, char rightkind)
{
const struct dropmsgstrings *rentry;
const struct dropmsgstrings *wentry;
for (rentry = dropmsgstringarray; rentry->kind != '\0'; rentry++)
if (rentry->kind == rightkind)
break;
Assert(rentry->kind != '\0');
for (wentry = dropmsgstringarray; wentry->kind != '\0'; wentry++)
if (wentry->kind == wrongkind)
break;
/* wrongkind could be something we don't have in our table... */
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg(rentry->nota_msg, relname),
(wentry->kind != '\0') ? errhint("%s", _(wentry->drophint_msg)) : 0));
}
/*
* RemoveRelations
* Implements DROP TABLE, DROP INDEX, DROP SEQUENCE, DROP VIEW
*/
void
RemoveRelations(DropStmt *drop)
{
ObjectAddresses *objects;
char relkind;
ListCell *cell;
/*
* First we identify all the relations, then we delete them in a single
* performMultipleDeletions() call. This is to avoid unwanted DROP
* RESTRICT errors if one of the relations depends on another.
*/
/* Determine required relkind */
switch (drop->removeType)
{
case OBJECT_TABLE:
relkind = RELKIND_RELATION;
break;
case OBJECT_INDEX:
relkind = RELKIND_INDEX;
break;
case OBJECT_SEQUENCE:
relkind = RELKIND_SEQUENCE;
break;
case OBJECT_VIEW:
relkind = RELKIND_VIEW; break;
default:
elog(ERROR, "unrecognized drop object type: %d",
(int) drop->removeType);
relkind = 0; /* keep compiler quiet */
break;
}
/* Lock and validate each relation; build a list of object addresses */
objects = new_object_addresses();
foreach(cell, drop->objects)
{
RangeVar *rel = makeRangeVarFromNameList((List *) lfirst(cell));
Oid relOid;
HeapTuple tuple;
Form_pg_class classform;
ObjectAddress obj;
/*
* These next few steps are a great deal like relation_openrv, but we
* don't bother building a relcache entry since we don't need it.
*
* Check for shared-cache-inval messages before trying to access the
* relation. This is needed to cover the case where the name
* identifies a rel that has been dropped and recreated since the
* start of our transaction: if we don't flush the old syscache entry,
* then we'll latch onto that entry and suffer an error later.
*/
AcceptInvalidationMessages();
/* Look up the appropriate relation using namespace search */
relOid = RangeVarGetRelid(rel, true);
/* Not there? */
if (!OidIsValid(relOid))
{
DropErrorMsgNonExistent(rel->relname, relkind, drop->missing_ok);
continue;
}
/*
* In DROP INDEX, attempt to acquire lock on the parent table before
* locking the index. index_drop() will need this anyway, and since
* regular queries lock tables before their indexes, we risk deadlock
* if we do it the other way around. No error if we don't find a
* pg_index entry, though --- that most likely means it isn't an
* index, and we'll fail below.
*/
if (relkind == RELKIND_INDEX)
{
tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(relOid));
if (HeapTupleIsValid(tuple))
{
Form_pg_index index = (Form_pg_index) GETSTRUCT(tuple);
LockRelationOid(index->indrelid, AccessExclusiveLock);
ReleaseSysCache(tuple);
}
}
/* Get the lock before trying to fetch the syscache entry */
LockRelationOid(relOid, AccessExclusiveLock);
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relOid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relOid);
classform = (Form_pg_class) GETSTRUCT(tuple);
if (classform->relkind != relkind)
DropErrorMsgWrongType(rel->relname, classform->relkind, relkind);
/* Allow DROP to either table owner or schema owner */
if (!pg_class_ownercheck(relOid, GetUserId()) &&
!pg_namespace_ownercheck(classform->relnamespace, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
rel->relname);
if (!allowSystemTableMods && IsSystemClass(classform))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
rel->relname)));
/* OK, we're ready to delete this one */
obj.classId = RelationRelationId;
obj.objectId = relOid;
obj.objectSubId = 0;
add_exact_object_address(&obj, objects);
ReleaseSysCache(tuple);
}
performMultipleDeletions(objects, drop->behavior);
free_object_addresses(objects);
}
/*
* ExecuteTruncate
* Executes a TRUNCATE command.
*
* This is a multi-relation truncate. We first open and grab exclusive
* lock on all relations involved, checking permissions and otherwise
* verifying that the relation is OK for truncation. In CASCADE mode,
* relations having FK references to the targeted relations are automatically
* added to the group; in RESTRICT mode, we check that all FK references are
* internal to the group that's being truncated. Finally all the relations
* are truncated and reindexed.
*/
void
ExecuteTruncate(TruncateStmt *stmt)
{
List *rels = NIL;
List *relids = NIL;
List *seq_relids = NIL;
EState *estate;
ResultRelInfo *resultRelInfos;
ResultRelInfo *resultRelInfo;
SubTransactionId mySubid;
ListCell *cell;
/*
* Open, exclusive-lock, and check all the explicitly-specified relations
*/
foreach(cell, stmt->relations)
{
RangeVar *rv = lfirst(cell);
Relation rel;
bool recurse = interpretInhOption(rv->inhOpt);
Oid myrelid;
rel = heap_openrv(rv, AccessExclusiveLock);
myrelid = RelationGetRelid(rel);
/* don't throw error for "TRUNCATE foo, foo" */
if (list_member_oid(relids, myrelid))
{
heap_close(rel, AccessExclusiveLock); continue;
}
truncate_check_rel(rel);
rels = lappend(rels, rel);
relids = lappend_oid(relids, myrelid);
if (recurse)
{
ListCell *child;
List *children;
children = find_all_inheritors(myrelid, AccessExclusiveLock, NULL);
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
if (list_member_oid(relids, childrelid))
continue;
/* find_all_inheritors already got lock */
rel = heap_open(childrelid, NoLock);
truncate_check_rel(rel);
rels = lappend(rels, rel);
relids = lappend_oid(relids, childrelid);
}
}
}
/*
* In CASCADE mode, suck in all referencing relations as well. This
* requires multiple iterations to find indirectly-dependent relations. At
* each phase, we need to exclusive-lock new rels before looking for their
* dependencies, else we might miss something. Also, we check each rel as
* soon as we open it, to avoid a faux pas such as holding lock for a long
* time on a rel we have no permissions for.
*/
if (stmt->behavior == DROP_CASCADE)
{
for (;;)
{
List *newrelids;
newrelids = heap_truncate_find_FKs(relids);
if (newrelids == NIL)
break; /* nothing else to add */
foreach(cell, newrelids)
{
Oid relid = lfirst_oid(cell);
Relation rel;
rel = heap_open(relid, AccessExclusiveLock);
ereport(NOTICE,
(errmsg("truncate cascades to table \"%s\"",
RelationGetRelationName(rel))));
truncate_check_rel(rel);
rels = lappend(rels, rel);
relids = lappend_oid(relids, relid);
}
}
}
/*
* Check foreign key references. In CASCADE mode, this should be
* unnecessary since we just pulled in all the references; but as a
* cross-check, do it anyway if in an Assert-enabled build.
*/
#ifdef USE_ASSERT_CHECKING
heap_truncate_check_FKs(rels, false);#else
if (stmt->behavior == DROP_RESTRICT)
heap_truncate_check_FKs(rels, false);
#endif
/*
* If we are asked to restart sequences, find all the sequences, lock them
* (we only need AccessShareLock because that's all that ALTER SEQUENCE
* takes), and check permissions. We want to do this early since it's
* pointless to do all the truncation work only to fail on sequence
* permissions.
*/
if (stmt->restart_seqs)
{
foreach(cell, rels)
{
Relation rel = (Relation) lfirst(cell);
List *seqlist = getOwnedSequences(RelationGetRelid(rel));
ListCell *seqcell;
foreach(seqcell, seqlist)
{
Oid seq_relid = lfirst_oid(seqcell);
Relation seq_rel;
seq_rel = relation_open(seq_relid, AccessShareLock);
/* This check must match AlterSequence! */
if (!pg_class_ownercheck(seq_relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(seq_rel));
seq_relids = lappend_oid(seq_relids, seq_relid);
relation_close(seq_rel, NoLock);
}
}
}
/* Prepare to catch AFTER triggers. */
AfterTriggerBeginQuery();
/*
* To fire triggers, we'll need an EState as well as a ResultRelInfo for
* each relation.
*/
estate = CreateExecutorState();
resultRelInfos = (ResultRelInfo *)
palloc(list_length(rels) * sizeof(ResultRelInfo));
resultRelInfo = resultRelInfos;
foreach(cell, rels)
{
Relation rel = (Relation) lfirst(cell);
InitResultRelInfo(resultRelInfo,
rel,
0, /* dummy rangetable index */
CMD_DELETE, /* don't need any index info */
0);
resultRelInfo++;
}
estate->es_result_relations = resultRelInfos;
estate->es_num_result_relations = list_length(rels);
/*
* Process all BEFORE STATEMENT TRUNCATE triggers before we begin
* truncating (this is because one of them might throw an error). Also, if
* we were to allow them to prevent statement execution, that would need
* to be handled here.
*/ resultRelInfo = resultRelInfos;
foreach(cell, rels)
{
estate->es_result_relation_info = resultRelInfo;
ExecBSTruncateTriggers(estate, resultRelInfo);
resultRelInfo++;
}
/*
* OK, truncate each table.
*/
mySubid = GetCurrentSubTransactionId();
foreach(cell, rels)
{
Relation rel = (Relation) lfirst(cell);
/*
* Normally, we need a transaction-safe truncation here. However, if
* the table was either created in the current (sub)transaction or has
* a new relfilenode in the current (sub)transaction, then we can just
* truncate it in-place, because a rollback would cause the whole
* table or the current physical file to be thrown away anyway.
*/
if (rel->rd_createSubid == mySubid ||
rel->rd_newRelfilenodeSubid == mySubid)
{
/* Immediate, non-rollbackable truncation is OK */
heap_truncate_one_rel(rel);
}
else
{
Oid heap_relid;
Oid toast_relid;
/*
* Need the full transaction-safe pushups.
*
* Create a new empty storage file for the relation, and assign it
* as the relfilenode value. The old storage file is scheduled for
* deletion at commit.
*/
RelationSetNewRelfilenode(rel, RecentXmin);
heap_relid = RelationGetRelid(rel);
toast_relid = rel->rd_rel->reltoastrelid;
/*
* The same for the toast table, if any.
*/
if (OidIsValid(toast_relid))
{
rel = relation_open(toast_relid, AccessExclusiveLock);
RelationSetNewRelfilenode(rel, RecentXmin);
heap_close(rel, NoLock);
}
/*
* Reconstruct the indexes to match, and we're done.
*/
reindex_relation(heap_relid, true, false);
}
}
/*
* Process all AFTER STATEMENT TRUNCATE triggers.
*/
resultRelInfo = resultRelInfos;
foreach(cell, rels)
{ estate->es_result_relation_info = resultRelInfo;
ExecASTruncateTriggers(estate, resultRelInfo);
resultRelInfo++;
}
/* Handle queued AFTER triggers */
AfterTriggerEndQuery(estate);
/* We can clean up the EState now */
FreeExecutorState(estate);
/* And close the rels (can't do this while EState still holds refs) */
foreach(cell, rels)
{
Relation rel = (Relation) lfirst(cell);
heap_close(rel, NoLock);
}
/*
* Lastly, restart any owned sequences if we were asked to. This is done
* last because it's nontransactional: restarts will not roll back if we
* abort later. Hence it's important to postpone them as long as
* possible. (This is also a big reason why we locked and
* permission-checked the sequences beforehand.)
*/
if (stmt->restart_seqs)
{
List *options = list_make1(makeDefElem("restart", NULL));
foreach(cell, seq_relids)
{
Oid seq_relid = lfirst_oid(cell);
AlterSequenceInternal(seq_relid, options);
}
}
}
/*
* Check that a given rel is safe to truncate. Subroutine for ExecuteTruncate
*/
static void
truncate_check_rel(Relation rel)
{
AclResult aclresult;
/* Only allow truncate on regular tables */
if (rel->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
RelationGetRelationName(rel))));
/* Permissions checks */
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_TRUNCATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(rel));
if (!allowSystemTableMods && IsSystemRelation(rel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(rel))));
/*
* Don't allow truncate on temp tables of other backends ... their local
* buffer manager is not going to cope. */
if (RELATION_IS_OTHER_TEMP(rel))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot truncate temporary tables of other sessions")));
/*
* Also check for active uses of the relation in the current transaction,
* including open scans and pending AFTER trigger events.
*/
CheckTableNotInUse(rel, "TRUNCATE");
}
/*
* storage_name
* returns the name corresponding to a typstorage/attstorage enum value
*/
static const char *
storage_name(char c)
{
switch (c)
{
case 'p':
return "PLAIN";
case 'm':
return "MAIN";
case 'x':
return "EXTENDED";
case 'e':
return "EXTERNAL";
default:
return "???";
}
}
/*----------
* MergeAttributes
* Returns new schema given initial schema and superclasses.
*
* Input arguments:
* 'schema' is the column/attribute definition for the table. (It's a list
* of ColumnDef's.) It is destructively changed.
* 'supers' is a list of names (as RangeVar nodes) of parent relations.
* 'istemp' is TRUE if we are creating a temp relation.
*
* Output arguments:
* 'supOids' receives a list of the OIDs of the parent relations.
* 'supconstr' receives a list of constraints belonging to the parents,
* updated as necessary to be valid for the child.
* 'supOidCount' is set to the number of parents that have OID columns.
*
* Return value:
* Completed schema list.
*
* Notes:
* The order in which the attributes are inherited is very important.
* Intuitively, the inherited attributes should come first. If a table
* inherits from multiple parents, the order of those attributes are
* according to the order of the parents specified in CREATE TABLE.
*
* Here's an example:
*
* create table person (name text, age int4, location point);
* create table emp (salary int4, manager text) inherits(person);
* create table student (gpa float8) inherits (person);
* create table stud_emp (percent int4) inherits (emp, student);
*
* The order of the attributes of stud_emp is:
*
* person {1:name, 2:age, 3:location} * / \
* {6:gpa} student emp {4:salary, 5:manager}
* \ /
* stud_emp {7:percent}
*
* If the same attribute name appears multiple times, then it appears
* in the result table in the proper location for its first appearance.
*
* Constraints (including NOT NULL constraints) for the child table
* are the union of all relevant constraints, from both the child schema
* and parent tables.
*
* The default value for a child column is defined as:
* (1) If the child schema specifies a default, that value is used.
* (2) If neither the child nor any parent specifies a default, then
* the column will not have a default.
* (3) If conflicting defaults are inherited from different parents
* (and not overridden by the child), an error is raised.
* (4) Otherwise the inherited default is used.
* Rule (3) is new in Postgres 7.1; in earlier releases you got a
* rather arbitrary choice of which parent default to use.
*----------
*/
static List *
MergeAttributes(List *schema, List *supers, bool istemp,
List **supOids, List **supconstr, int *supOidCount)
{
ListCell *entry;
List *inhSchema = NIL;
List *parentOids = NIL;
List *constraints = NIL;
int parentsWithOids = 0;
bool have_bogus_defaults = false;
int child_attno;
static Node bogus_marker = {0}; /* marks conflicting defaults */
/*
* Check for and reject tables with too many columns. We perform this
* check relatively early for two reasons: (a) we don't run the risk of
* overflowing an AttrNumber in subsequent code (b) an O(n^2) algorithm is
* okay if we're processing <= 1600 columns, but could take minutes to
* execute if the user attempts to create a table with hundreds of
* thousands of columns.
*
* Note that we also need to check that any we do not exceed this figure
* after including columns from inherited relations.
*/
if (list_length(schema) > MaxHeapAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("tables can have at most %d columns",
MaxHeapAttributeNumber)));
/*
* Check for duplicate names in the explicit list of attributes.
*
* Although we might consider merging such entries in the same way that we
* handle name conflicts for inherited attributes, it seems to make more
* sense to assume such conflicts are errors.
*/
foreach(entry, schema)
{
ColumnDef *coldef = lfirst(entry);
ListCell *rest = lnext(entry);
ListCell *prev = entry;
if (coldef->typeName == NULL)
/*
* Typed table column option that does not belong to a column from * the type. This works because the columns from the type come
* first in the list.
*/
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" does not exist",
coldef->colname)));
while (rest != NULL)
{
ColumnDef *restdef = lfirst(rest);
ListCell *next = lnext(rest); /* need to save it in case we
* delete it */
if (strcmp(coldef->colname, restdef->colname) == 0)
{
if (coldef->is_from_type)
{
/*
* merge the column options into the column from the type
*/
coldef->is_not_null = restdef->is_not_null;
coldef->raw_default = restdef->raw_default;
coldef->cooked_default = restdef->cooked_default;
coldef->constraints = restdef->constraints;
coldef->is_from_type = false;
list_delete_cell(schema, rest, prev);
}
else
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" specified more than once",
coldef->colname)));
}
prev = rest;
rest = next;
}
}
/*
* Scan the parents left-to-right, and merge their attributes to form a
* list of inherited attributes (inhSchema). Also check to see if we need
* to inherit an OID column.
*/
child_attno = 0;
foreach(entry, supers)
{
RangeVar *parent = (RangeVar *) lfirst(entry);
Relation relation;
TupleDesc tupleDesc;
TupleConstr *constr;
AttrNumber *newattno;
AttrNumber parent_attno;
relation = heap_openrv(parent, AccessShareLock);
if (relation->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("inherited relation \"%s\" is not a table",
parent->relname)));
/* Permanent rels cannot inherit from temporary ones */
if (!istemp && relation->rd_istemp)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot inherit from temporary relation \"%s\"",
parent->relname)));
/*
* We should have an UNDER permission flag for this, but for now, * demand that creator of a child table own the parent.
*/
if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(relation));
/*
* Reject duplications in the list of parents.
*/
if (list_member_oid(parentOids, RelationGetRelid(relation)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" would be inherited from more than once",
parent->relname)));
parentOids = lappend_oid(parentOids, RelationGetRelid(relation));
if (relation->rd_rel->relhasoids)
parentsWithOids++;
tupleDesc = RelationGetDescr(relation);
constr = tupleDesc->constr;
/*
* newattno[] will contain the child-table attribute numbers for the
* attributes of this parent table. (They are not the same for
* parents after the first one, nor if we have dropped columns.)
*/
newattno = (AttrNumber *)
palloc(tupleDesc->natts * sizeof(AttrNumber));
for (parent_attno = 1; parent_attno <= tupleDesc->natts;
parent_attno++)
{
Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
char *attributeName = NameStr(attribute->attname);
int exist_attno;
ColumnDef *def;
/*
* Ignore dropped columns in the parent.
*/
if (attribute->attisdropped)
{
/*
* change_varattnos_of_a_node asserts that this is greater
* than zero, so if anything tries to use it, we should find
* out.
*/
newattno[parent_attno - 1] = 0;
continue;
}
/*
* Does it conflict with some previously inherited column?
*/
exist_attno = findAttrByName(attributeName, inhSchema);
if (exist_attno > 0)
{
Oid defTypeId;
int32 deftypmod;
/*
* Yes, try to merge the two column definitions. They must
* have the same type and typmod.
*/
ereport(NOTICE,
(errmsg("merging multiple inherited definitions of column \"%s\"",
attributeName)));
def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1); defTypeId = typenameTypeId(NULL, def->typeName, &deftypmod);
if (defTypeId != attribute->atttypid ||
deftypmod != attribute->atttypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("inherited column \"%s\" has a type conflict",
attributeName),
errdetail("%s versus %s",
TypeNameToString(def->typeName),
format_type_be(attribute->atttypid))));
/* Copy storage parameter */
if (def->storage == 0)
def->storage = attribute->attstorage;
else if (def->storage != attribute->attstorage)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("inherited column \"%s\" has a storage parameter conflict",
attributeName),
errdetail("%s versus %s",
storage_name(def->storage),
storage_name(attribute->attstorage))));
def->inhcount++;
/* Merge of NOT NULL constraints = OR 'em together */
def->is_not_null |= attribute->attnotnull;
/* Default and other constraints are handled below */
newattno[parent_attno - 1] = exist_attno;
}
else
{
/*
* No, create a new inherited column
*/
def = makeNode(ColumnDef);
def->colname = pstrdup(attributeName);
def->typeName = makeTypeNameFromOid(attribute->atttypid,
attribute->atttypmod);
def->inhcount = 1;
def->is_local = false;
def->is_not_null = attribute->attnotnull;
def->storage = attribute->attstorage;
def->raw_default = NULL;
def->cooked_default = NULL;
def->constraints = NIL;
inhSchema = lappend(inhSchema, def);
newattno[parent_attno - 1] = ++child_attno;
}
/*
* Copy default if any
*/
if (attribute->atthasdef)
{
Node *this_default = NULL;
AttrDefault *attrdef;
int i;
/* Find default in constraint structure */
Assert(constr != NULL);
attrdef = constr->defval;
for (i = 0; i < constr->num_defval; i++)
{
if (attrdef[i].adnum == parent_attno)
{
this_default = stringToNode(attrdef[i].adbin);
break;
}
}
Assert(this_default != NULL);
/*
* If default expr could contain any vars, we'd need to fix
* 'em, but it can't; so default is ready to apply to child.
*
* If we already had a default from some prior parent, check
* to see if they are the same. If so, no problem; if not,
* mark the column as having a bogus default. Below, we will
* complain if the bogus default isn't overridden by the child
* schema.
*/
Assert(def->raw_default == NULL);
if (def->cooked_default == NULL)
def->cooked_default = this_default;
else if (!equal(def->cooked_default, this_default))
{
def->cooked_default = &bogus_marker;
have_bogus_defaults = true;
}
}
}
/*
* Now copy the CHECK constraints of this parent, adjusting attnos
* using the completed newattno[] map. Identically named constraints
* are merged if possible, else we throw error.
*/
if (constr && constr->num_check > 0)
{
ConstrCheck *check = constr->check;
int i;
for (i = 0; i < constr->num_check; i++)
{
char *name = check[i].ccname;
Node *expr;
/* adjust varattnos of ccbin here */
expr = stringToNode(check[i].ccbin);
change_varattnos_of_a_node(expr, newattno);
/* check for duplicate */
if (!MergeCheckConstraint(constraints, name, expr))
{
/* nope, this is a new one */
CookedConstraint *cooked;
cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
cooked->contype = CONSTR_CHECK;
cooked->name = pstrdup(name);
cooked->attnum = 0; /* not used for constraints */
cooked->expr = expr;
cooked->is_local = false;
cooked->inhcount = 1;
constraints = lappend(constraints, cooked);
}
}
}
pfree(newattno);
/*
* Close the parent rel, but keep our AccessShareLock on it until xact
* commit. That will prevent someone else from deleting or ALTERing
* the parent before the child is committed.
*/
heap_close(relation, NoLock);
}
/* * If we had no inherited attributes, the result schema is just the
* explicitly declared columns. Otherwise, we need to merge the declared
* columns into the inherited schema list.
*/
if (inhSchema != NIL)
{
foreach(entry, schema)
{
ColumnDef *newdef = lfirst(entry);
char *attributeName = newdef->colname;
int exist_attno;
/*
* Does it conflict with some previously inherited column?
*/
exist_attno = findAttrByName(attributeName, inhSchema);
if (exist_attno > 0)
{
ColumnDef *def;
Oid defTypeId,
newTypeId;
int32 deftypmod,
newtypmod;
/*
* Yes, try to merge the two column definitions. They must
* have the same type and typmod.
*/
ereport(NOTICE,
(errmsg("merging column \"%s\" with inherited definition",
attributeName)));
def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1);
defTypeId = typenameTypeId(NULL, def->typeName, &deftypmod);
newTypeId = typenameTypeId(NULL, newdef->typeName, &newtypmod);
if (defTypeId != newTypeId || deftypmod != newtypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" has a type conflict",
attributeName),
errdetail("%s versus %s",
TypeNameToString(def->typeName),
TypeNameToString(newdef->typeName))));
/* Copy storage parameter */
if (def->storage == 0)
def->storage = newdef->storage;
else if (newdef->storage != 0 && def->storage != newdef->storage)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" has a storage parameter conflict",
attributeName),
errdetail("%s versus %s",
storage_name(def->storage),
storage_name(newdef->storage))));
/* Mark the column as locally defined */
def->is_local = true;
/* Merge of NOT NULL constraints = OR 'em together */
def->is_not_null |= newdef->is_not_null;
/* If new def has a default, override previous default */
if (newdef->raw_default != NULL)
{
def->raw_default = newdef->raw_default;
def->cooked_default = newdef->cooked_default;
}
}
else
{
/*
* No, attach new column to result schema */
inhSchema = lappend(inhSchema, newdef);
}
}
schema = inhSchema;
/*
* Check that we haven't exceeded the legal # of columns after merging
* in inherited columns.
*/
if (list_length(schema) > MaxHeapAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("tables can have at most %d columns",
MaxHeapAttributeNumber)));
}
/*
* If we found any conflicting parent default values, check to make sure
* they were overridden by the child.
*/
if (have_bogus_defaults)
{
foreach(entry, schema)
{
ColumnDef *def = lfirst(entry);
if (def->cooked_default == &bogus_marker)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
errmsg("column \"%s\" inherits conflicting default values",
def->colname),
errhint("To resolve the conflict, specify a default explicitly.")));
}
}
*supOids = parentOids;
*supconstr = constraints;
*supOidCount = parentsWithOids;
return schema;
}
/*
* MergeCheckConstraint
* Try to merge an inherited CHECK constraint with previous ones
*
* If we inherit identically-named constraints from multiple parents, we must
* merge them, or throw an error if they don't have identical definitions.
*
* constraints is a list of CookedConstraint structs for previous constraints.
*
* Returns TRUE if merged (constraint is a duplicate), or FALSE if it's
* got a so-far-unique name, or throws error if conflict.
*/
static bool
MergeCheckConstraint(List *constraints, char *name, Node *expr)
{
ListCell *lc;
foreach(lc, constraints)
{
CookedConstraint *ccon = (CookedConstraint *) lfirst(lc);
Assert(ccon->contype == CONSTR_CHECK);
/* Non-matching names never conflict */
if (strcmp(ccon->name, name) != 0)
continue;
if (equal(expr, ccon->expr))
{
/* OK to merge */
ccon->inhcount++;
return true;
}
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("check constraint name \"%s\" appears multiple times but with different expressions",
name)));
}
return false;
}
/*
* Replace varattno values in an expression tree according to the given
* map array, that is, varattno N is replaced by newattno[N-1]. It is
* caller's responsibility to ensure that the array is long enough to
* define values for all user varattnos present in the tree. System column
* attnos remain unchanged.
*
* Note that the passed node tree is modified in-place!
*/
void
change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
{
/* no setup needed, so away we go */
(void) change_varattnos_walker(node, newattno);
}
static bool
change_varattnos_walker(Node *node, const AttrNumber *newattno)
{
if (node == NULL)
return false;
if (IsA(node, Var))
{
Var *var = (Var *) node;
if (var->varlevelsup == 0 && var->varno == 1 &&
var->varattno > 0)
{
/*
* ??? the following may be a problem when the node is multiply
* referenced though stringToNode() doesn't create such a node
* currently.
*/
Assert(newattno[var->varattno - 1] > 0);
var->varattno = var->varoattno = newattno[var->varattno - 1];
}
return false;
}
return expression_tree_walker(node, change_varattnos_walker,
(void *) newattno);
}
/*
* Generate a map for change_varattnos_of_a_node from old and new TupleDesc's,
* matching according to column name.
*/
AttrNumber *
varattnos_map(TupleDesc olddesc, TupleDesc newdesc)
{
AttrNumber *attmap;
int i,
j;
attmap = (AttrNumber *) palloc0(sizeof(AttrNumber) * olddesc->natts);
for (i = 1; i <= olddesc->natts; i++)
{
if (olddesc->attrs[i - 1]->attisdropped)
continue; /* leave the entry as zero */
for (j = 1; j <= newdesc->natts; j++)
{
if (strcmp(NameStr(olddesc->attrs[i - 1]->attname),
NameStr(newdesc->attrs[j - 1]->attname)) == 0)
{
attmap[i - 1] = j;
break;
}
}
}
return attmap;
}
/*
* Generate a map for change_varattnos_of_a_node from a TupleDesc and a list
* of ColumnDefs
*/
AttrNumber *
varattnos_map_schema(TupleDesc old, List *schema)
{
AttrNumber *attmap;
int i;
attmap = (AttrNumber *) palloc0(sizeof(AttrNumber) * old->natts);
for (i = 1; i <= old->natts; i++)
{
if (old->attrs[i - 1]->attisdropped)
continue; /* leave the entry as zero */
attmap[i - 1] = findAttrByName(NameStr(old->attrs[i - 1]->attname),
schema);
}
return attmap;
}
/*
* StoreCatalogInheritance
* Updates the system catalogs with proper inheritance information.
*
* supers is a list of the OIDs of the new relation's direct ancestors.
*/
static void
StoreCatalogInheritance(Oid relationId, List *supers)
{
Relation relation;
int16 seqNumber;
ListCell *entry;
/*
* sanity checks
*/
AssertArg(OidIsValid(relationId));
if (supers == NIL)
return;
/*
* Store INHERITS information in pg_inherits using direct ancestors only.
* Also enter dependencies on the direct ancestors, and make sure they are
* marked with relhassubclass = true.
*
* (Once upon a time, both direct and indirect ancestors were found here * and then entered into pg_ipl. Since that catalog doesn't exist
* anymore, there's no need to look for indirect ancestors.)
*/
relation = heap_open(InheritsRelationId, RowExclusiveLock);
seqNumber = 1;
foreach(entry, supers)
{
Oid parentOid = lfirst_oid(entry);
StoreCatalogInheritance1(relationId, parentOid, seqNumber, relation);
seqNumber++;
}
heap_close(relation, RowExclusiveLock);
}
/*
* Make catalog entries showing relationId as being an inheritance child
* of parentOid. inhRelation is the already-opened pg_inherits catalog.
*/
static void
StoreCatalogInheritance1(Oid relationId, Oid parentOid,
int16 seqNumber, Relation inhRelation)
{
TupleDesc desc = RelationGetDescr(inhRelation);
Datum values[Natts_pg_inherits];
bool nulls[Natts_pg_inherits];
ObjectAddress childobject,
parentobject;
HeapTuple tuple;
/*
* Make the pg_inherits entry
*/
values[Anum_pg_inherits_inhrelid - 1] = ObjectIdGetDatum(relationId);
values[Anum_pg_inherits_inhparent - 1] = ObjectIdGetDatum(parentOid);
values[Anum_pg_inherits_inhseqno - 1] = Int16GetDatum(seqNumber);
memset(nulls, 0, sizeof(nulls));
tuple = heap_form_tuple(desc, values, nulls);
simple_heap_insert(inhRelation, tuple);
CatalogUpdateIndexes(inhRelation, tuple);
heap_freetuple(tuple);
/*
* Store a dependency too
*/
parentobject.classId = RelationRelationId;
parentobject.objectId = parentOid;
parentobject.objectSubId = 0;
childobject.classId = RelationRelationId;
childobject.objectId = relationId;
childobject.objectSubId = 0;
recordDependencyOn(&childobject, &parentobject, DEPENDENCY_NORMAL);
/*
* Mark the parent as having subclasses.
*/
setRelhassubclassInRelation(parentOid, true);
}
/*
* Look for an existing schema entry with the given name.
* * Returns the index (starting with 1) if attribute already exists in schema,
* 0 if it doesn't.
*/
static int
findAttrByName(const char *attributeName, List *schema)
{
ListCell *s;
int i = 1;
foreach(s, schema)
{
ColumnDef *def = lfirst(s);
if (strcmp(attributeName, def->colname) == 0)
return i;
i++;
}
return 0;
}
/*
* Update a relation's pg_class.relhassubclass entry to the given value
*/
static void
setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
{
Relation relationRelation;
HeapTuple tuple;
Form_pg_class classtuple;
/*
* Fetch a modifiable copy of the tuple, modify it, update pg_class.
*
* If the tuple already has the right relhassubclass setting, we don't
* need to update it, but we still need to issue an SI inval message.
*/
relationRelation = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relationId));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relationId);
classtuple = (Form_pg_class) GETSTRUCT(tuple);
if (classtuple->relhassubclass != relhassubclass)
{
classtuple->relhassubclass = relhassubclass;
simple_heap_update(relationRelation, &tuple->t_self, tuple);
/* keep the catalog indexes up to date */
CatalogUpdateIndexes(relationRelation, tuple);
}
else
{
/* no need to change tuple, but force relcache rebuild anyway */
CacheInvalidateRelcacheByTuple(tuple);
}
heap_freetuple(tuple);
heap_close(relationRelation, RowExclusiveLock);
}
/*
* renameatt - changes the name of a attribute in a relation
*/
void
renameatt(Oid myrelid,
const char *oldattname,
const char *newattname,
bool recurse, int expected_parents)
{
Relation targetrelation;
Relation attrelation;
HeapTuple atttup;
Form_pg_attribute attform;
int attnum;
char relkind;
/*
* Grab an exclusive lock on the target table, which we will NOT release
* until end of transaction.
*/
targetrelation = relation_open(myrelid, AccessExclusiveLock);
if (targetrelation->rd_rel->reloftype)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot rename column of typed table")));
/*
* Renaming the columns of sequences or toast tables doesn't actually
* break anything from the system's point of view, since internal
* references are by attnum. But it doesn't seem right to allow users to
* change names that are hardcoded into the system, hence the following
* restriction.
*/
relkind = RelationGetForm(targetrelation)->relkind;
if (relkind != RELKIND_RELATION &&
relkind != RELKIND_VIEW &&
relkind != RELKIND_COMPOSITE_TYPE &&
relkind != RELKIND_INDEX)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table, view, composite type or index",
RelationGetRelationName(targetrelation))));
/*
* permissions checking. only the owner of a class can change its schema.
*/
if (!pg_class_ownercheck(myrelid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(targetrelation));
if (!allowSystemTableMods && IsSystemRelation(targetrelation))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(targetrelation))));
/*
* if the 'recurse' flag is set then we are supposed to rename this
* attribute in all classes that inherit from 'relname' (as well as in
* 'relname').
*
* any permissions or problems with duplicate attributes will cause the
* whole transaction to abort, which is what we want -- all or nothing.
*/
if (recurse)
{
List *child_oids,
*child_numparents;
ListCell *lo,
*li;
/*
* we need the number of parents for each child so that the recursive
* calls to renameatt() can determine whether there are any parents
* outside the inheritance hierarchy being processed.
*/
child_oids = find_all_inheritors(myrelid, AccessExclusiveLock, &child_numparents);
/*
* find_all_inheritors does the recursive search of the inheritance
* hierarchy, so all we have to do is process all of the relids in the
* list that it returns.
*/
forboth(lo, child_oids, li, child_numparents)
{
Oid childrelid = lfirst_oid(lo);
int numparents = lfirst_int(li);
if (childrelid == myrelid)
continue;
/* note we need not recurse again */
renameatt(childrelid, oldattname, newattname, false, numparents);
}
}
else
{
/*
* If we are told not to recurse, there had better not be any child
* tables; else the rename would put them out of step.
*
* expected_parents will only be 0 if we are not already recursing.
*/
if (expected_parents == 0 &&
find_inheritance_children(myrelid, NoLock) != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("inherited column \"%s\" must be renamed in child tables too",
oldattname)));
}
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
atttup = SearchSysCacheCopyAttName(myrelid, oldattname);
if (!HeapTupleIsValid(atttup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" does not exist",
oldattname)));
attform = (Form_pg_attribute) GETSTRUCT(atttup);
attnum = attform->attnum;
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot rename system column \"%s\"",
oldattname)));
/*
* if the attribute is inherited, forbid the renaming. if this is a
* top-level call to renameatt(), then expected_parents will be 0, so the
* effect of this code will be to prohibit the renaming if the attribute
* is inherited at all. if this is a recursive call to renameatt(),
* expected_parents will be the number of parents the current relation has
* within the inheritance hierarchy being processed, so we'll prohibit the
* renaming only if there are additional parents from elsewhere.
*/
if (attform->attinhcount > expected_parents)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot rename inherited column \"%s\"",
oldattname)));
/* new name should not already exist */
/* this test is deliberately not attisdropped-aware */
if (SearchSysCacheExists2(ATTNAME, ObjectIdGetDatum(myrelid),
PointerGetDatum(newattname)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" of relation \"%s\" already exists",
newattname, RelationGetRelationName(targetrelation))));
/* apply the update */
namestrcpy(&(attform->attname), newattname);
simple_heap_update(attrelation, &atttup->t_self, atttup);
/* keep system catalog indexes current */
CatalogUpdateIndexes(attrelation, atttup);
heap_freetuple(atttup);
heap_close(attrelation, RowExclusiveLock);
relation_close(targetrelation, NoLock); /* close rel but keep lock */
}
/*
* Execute ALTER TABLE/INDEX/SEQUENCE/VIEW RENAME
*
* Caller has already done permissions checks.
*/
void
RenameRelation(Oid myrelid, const char *newrelname, ObjectType reltype)
{
Relation targetrelation;
Oid namespaceId;
char relkind;
/*
* Grab an exclusive lock on the target table, index, sequence or view,
* which we will NOT release until end of transaction.
*/
targetrelation = relation_open(myrelid, AccessExclusiveLock);
namespaceId = RelationGetNamespace(targetrelation);
relkind = targetrelation->rd_rel->relkind;
/*
* For compatibility with prior releases, we don't complain if ALTER TABLE
* or ALTER INDEX is used to rename a sequence or view.
*/
if (reltype == OBJECT_SEQUENCE && relkind != RELKIND_SEQUENCE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a sequence",
RelationGetRelationName(targetrelation))));
if (reltype == OBJECT_VIEW && relkind != RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a view",
RelationGetRelationName(targetrelation))));
/*
* Don't allow ALTER TABLE on composite types. We want people to use ALTER
* TYPE for that.
*/
if (relkind == RELKIND_COMPOSITE_TYPE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a composite type",
RelationGetRelationName(targetrelation)),
errhint("Use ALTER TYPE instead.")));
/* Do the work */
RenameRelationInternal(myrelid, newrelname, namespaceId);
/*
* Close rel, but keep exclusive lock!
*/
relation_close(targetrelation, NoLock);
}
/*
* RenameRelationInternal - change the name of a relation
*
* XXX - When renaming sequences, we don't bother to modify the
* sequence name that is stored within the sequence itself
* (this would cause problems with MVCC). In the future,
* the sequence name should probably be removed from the
* sequence, AFAIK there's no need for it to be there.
*/
void
RenameRelationInternal(Oid myrelid, const char *newrelname, Oid namespaceId)
{
Relation targetrelation;
Relation relrelation; /* for RELATION relation */
HeapTuple reltup;
Form_pg_class relform;
/*
* Grab an exclusive lock on the target table, index, sequence or view,
* which we will NOT release until end of transaction.
*/
targetrelation = relation_open(myrelid, AccessExclusiveLock);
/*
* Find relation's pg_class tuple, and make sure newrelname isn't in use.
*/
relrelation = heap_open(RelationRelationId, RowExclusiveLock);
reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(myrelid));
if (!HeapTupleIsValid(reltup)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for relation %u", myrelid);
relform = (Form_pg_class) GETSTRUCT(reltup);
if (get_relname_relid(newrelname, namespaceId) != InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" already exists",
newrelname)));
/*
* Update pg_class tuple with new relname. (Scribbling on reltup is OK
* because it's a copy...)
*/
namestrcpy(&(relform->relname), newrelname);
simple_heap_update(relrelation, &reltup->t_self, reltup);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(relrelation, reltup);
heap_freetuple(reltup);
heap_close(relrelation, RowExclusiveLock);
/*
* Also rename the associated type, if any.
*/
if (OidIsValid(targetrelation->rd_rel->reltype))
RenameTypeInternal(targetrelation->rd_rel->reltype,
newrelname, namespaceId);
/*
* Also rename the associated constraint, if any.
*/
if (targetrelation->rd_rel->relkind == RELKIND_INDEX)
{
Oid constraintId = get_index_constraint(myrelid);
if (OidIsValid(constraintId))
RenameConstraintById(constraintId, newrelname);
}
/*
* Close rel, but keep exclusive lock!
*/
relation_close(targetrelation, NoLock);
}
/*
* Disallow ALTER TABLE (and similar commands) when the current backend has
* any open reference to the target table besides the one just acquired by
* the calling command; this implies there's an open cursor or active plan.
* We need this check because our lock doesn't protect us against stomping
* on our own foot, only other people's feet!
*
* For ALTER TABLE, the only case known to cause serious trouble is ALTER
* COLUMN TYPE, and some changes are obviously pretty benign, so this could
* possibly be relaxed to only error out for certain types of alterations.
* But the use-case for allowing any of these things is not obvious, so we
* won't work hard at it for now.
*
* We also reject these commands if there are any pending AFTER trigger events
* for the rel. This is certainly necessary for the rewriting variants of
* ALTER TABLE, because they don't preserve tuple TIDs and so the pending
* events would try to fetch the wrong tuples. It might be overly cautious
* in other cases, but again it seems better to err on the side of paranoia.
*
* REINDEX calls this with "rel" referencing the index to be rebuilt; here
* we are worried about active indexscans on the index. The trigger-event
* check can be skipped, since we are doing no damage to the parent table.
*
* The statement name (eg, "ALTER TABLE") is passed for use in error messages.
*/
void
CheckTableNotInUse(Relation rel, const char *stmt)
{
int expected_refcnt;
expected_refcnt = rel->rd_isnailed ? 2 : 1;
if (rel->rd_refcnt != expected_refcnt)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
/* translator: first %s is a SQL command, eg ALTER TABLE */
errmsg("cannot %s \"%s\" because "
"it is being used by active queries in this session",
stmt, RelationGetRelationName(rel))));
if (rel->rd_rel->relkind != RELKIND_INDEX &&
AfterTriggerPendingOnRel(RelationGetRelid(rel)))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
/* translator: first %s is a SQL command, eg ALTER TABLE */
errmsg("cannot %s \"%s\" because "
"it has pending trigger events",
stmt, RelationGetRelationName(rel))));
}
/*
* AlterTable
* Execute ALTER TABLE, which can be a list of subcommands
* * ALTER TABLE is performed in three phases:
* 1. Examine subcommands and perform pre-transformation checking.
* 2. Update system catalogs.
* 3. Scan table(s) to check new constraints, and optionally recopy
* the data into new table(s).
* Phase 3 is not performed unless one or more of the subcommands requires
* it. The intention of this design is to allow multiple independent
* updates of the table schema to be performed with only one pass over the
* data.
*
* ATPrepCmd performs phase 1. A "work queue" entry is created for
* each table to be affected (there may be multiple affected tables if the
* commands traverse a table inheritance hierarchy). Also we do preliminary
* validation of the subcommands, including parse transformation of those
* expressions that need to be evaluated with respect to the old table
* schema.
*
* ATRewriteCatalogs performs phase 2 for each affected table. (Note that
* phases 2 and 3 normally do no explicit recursion, since phase 1 already
* did it --- although some subcommands have to recurse in phase 2 instead.)
* Certain subcommands need to be performed before others to avoid
* unnecessary conflicts; for example, DROP COLUMN should come before
* ADD COLUMN. Therefore phase 1 divides the subcommands into multiple
* lists, one for each logical "pass" of phase 2.
*
* ATRewriteTables performs phase 3 for those tables that need it.
*
* Thanks to the magic of MVCC, an error anywhere along the way rolls back
* the whole operation; we don't have to do anything special to clean up.
*
* We lock the table as the first action, with an appropriate lock level
* for the subcommands requested. Any subcommand that needs to rewrite
* tuples in the table forces the whole command to be executed with
* AccessExclusiveLock. If all subcommands do not require rewrite table
* then we may be able to use lower lock levels. We pass the lock level down
* so that we can apply it recursively to inherited tables. Note that the
* lock level we want as we recurse may well be higher than required for
* that specific subcommand. So we pass down the overall lock requirement,
* rather than reassess it at lower levels.
*/
void
AlterTable(AlterTableStmt *stmt)
{
Relation rel;
LOCKMODE lockmode = AlterTableGetLockLevel(stmt->cmds);
/*
* Acquire same level of lock as already acquired during parsing.
*/
rel = relation_openrv(stmt->relation, lockmode);
CheckTableNotInUse(rel, "ALTER TABLE");
/* Check relation type against type specified in the ALTER command */
switch (stmt->relkind)
{
case OBJECT_TABLE:
/*
* For mostly-historical reasons, we allow ALTER TABLE to apply to
* all relation types.
*/
break;
case OBJECT_INDEX:
if (rel->rd_rel->relkind != RELKIND_INDEX)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not an index",
RelationGetRelationName(rel)))); break;
case OBJECT_SEQUENCE:
if (rel->rd_rel->relkind != RELKIND_SEQUENCE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a sequence",
RelationGetRelationName(rel))));
break;
case OBJECT_VIEW:
if (rel->rd_rel->relkind != RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a view",
RelationGetRelationName(rel))));
break;
default:
elog(ERROR, "unrecognized object type: %d", (int) stmt->relkind);
}
ATController(rel, stmt->cmds, interpretInhOption(stmt->relation->inhOpt),
lockmode);
}
/*
* AlterTableInternal
*
* ALTER TABLE with target specified by OID
*
* We do not reject if the relation is already open, because it's quite
* likely that one or more layers of caller have it open. That means it
* is unsafe to use this entry point for alterations that could break
* existing query plans. On the assumption it's not used for such, we
* don't have to reject pending AFTER triggers, either.
*/
void
AlterTableInternal(Oid relid, List *cmds, bool recurse)
{
Relation rel;
LOCKMODE lockmode = AlterTableGetLockLevel(cmds);
rel = relation_open(relid, lockmode);
ATController(rel, cmds, recurse, lockmode);
}
/*
* AlterTableGetLockLevel
*
* Sets the overall lock level required for the supplied list of subcommands.
* Policy for doing this set according to needs of AlterTable(), see
* comments there for overall explanation.
*
* Function is called before and after parsing, so it must give same
* answer each time it is called. Some subcommands are transformed
* into other subcommand types, so the transform must never be made to a
* lower lock level than previously assigned. All transforms are noted below.
*
* Since this is called before we lock the table we cannot use table metadata
* to influence the type of lock we acquire.
*
* There should be no lockmodes hardcoded into the subcommand functions. All
* lockmode decisions for ALTER TABLE are made here only. The one exception is
* ALTER TABLE RENAME which is treated as a different statement type T_RenameStmt
* and does not travel through this section of code and cannot be combined with
* any of the subcommands given here.
*/
LOCKMODEAlterTableGetLockLevel(List *cmds)
{
ListCell *lcmd;
LOCKMODE lockmode = ShareUpdateExclusiveLock;
foreach(lcmd, cmds)
{
AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
LOCKMODE cmd_lockmode = AccessExclusiveLock; /* default for compiler */
switch (cmd->subtype)
{
/*
* Need AccessExclusiveLock for these subcommands because they
* affect or potentially affect both read and write operations.
*
* New subcommand types should be added here by default.
*/
case AT_AddColumn: /* may rewrite heap, in some cases and visible to SELECT */
case AT_DropColumn: /* change visible to SELECT */
case AT_AddColumnToView: /* CREATE VIEW */
case AT_AlterColumnType: /* must rewrite heap */
case AT_DropConstraint: /* as DROP INDEX */
case AT_AddOids: /* must rewrite heap */
case AT_DropOids: /* calls AT_DropColumn */
case AT_EnableAlwaysRule: /* may change SELECT rules */
case AT_EnableReplicaRule: /* may change SELECT rules */
case AT_EnableRule: /* may change SELECT rules */
case AT_DisableRule: /* may change SELECT rules */
case AT_ChangeOwner: /* change visible to SELECT */
case AT_SetTableSpace: /* must rewrite heap */
case AT_DropNotNull: /* may change some SQL plans */
case AT_SetNotNull:
cmd_lockmode = AccessExclusiveLock;
break;
/*
* These subcommands affect write operations only.
*/
case AT_ColumnDefault:
case AT_ProcessedConstraint: /* becomes AT_AddConstraint */
case AT_AddConstraintRecurse: /* becomes AT_AddConstraint */
case AT_EnableTrig:
case AT_EnableAlwaysTrig:
case AT_EnableReplicaTrig:
case AT_EnableTrigAll:
case AT_EnableTrigUser:
case AT_DisableTrig:
case AT_DisableTrigAll:
case AT_DisableTrigUser:
case AT_AddIndex: /* from ADD CONSTRAINT */
cmd_lockmode = ShareRowExclusiveLock;
break;
case AT_AddConstraint:
if (IsA(cmd->def, Constraint))
{
Constraint *con = (Constraint *) cmd->def;
switch (con->contype)
{
case CONSTR_EXCLUSION:
case CONSTR_PRIMARY:
case CONSTR_UNIQUE:
/*
* Cases essentially the same as CREATE INDEX. We
* could reduce the lock strength to ShareLock if we
* can work out how to allow concurrent catalog updates.
*/
cmd_lockmode = ShareRowExclusiveLock; break;
case CONSTR_FOREIGN:
/*
* We add triggers to both tables when we add a
* Foreign Key, so the lock level must be at least
* as strong as CREATE TRIGGER.
*/
cmd_lockmode = ShareRowExclusiveLock;
break;
default:
cmd_lockmode = ShareRowExclusiveLock;
}
}
break;
/*
* These subcommands affect inheritance behaviour. Queries started before us
* will continue to see the old inheritance behaviour, while queries started
* after we commit will see new behaviour. No need to prevent reads or writes
* to the subtable while we hook it up though. In both cases the parent table
* is locked with AccessShareLock.
*/
case AT_AddInherit:
case AT_DropInherit:
cmd_lockmode = ShareUpdateExclusiveLock;
break;
/*
* These subcommands affect general strategies for performance and maintenance,
* though don't change the semantic results from normal data reads and writes.
* Delaying an ALTER TABLE behind currently active writes only delays the point
* where the new strategy begins to take effect, so there is no benefit in waiting.
* In thise case the minimum restriction applies: we don't currently allow
* concurrent catalog updates.
*/
case AT_SetStatistics:
case AT_ClusterOn:
case AT_DropCluster:
case AT_SetRelOptions:
case AT_ResetRelOptions:
case AT_SetOptions:
case AT_ResetOptions:
case AT_SetStorage:
cmd_lockmode = ShareUpdateExclusiveLock;
break;
default: /* oops */
elog(ERROR, "unrecognized alter table type: %d",
(int) cmd->subtype);
break;
}
/*
* Take the greatest lockmode from any subcommand
*/
if (cmd_lockmode > lockmode)
lockmode = cmd_lockmode;
}
return lockmode;
}
static void
ATController(Relation rel, List *cmds, bool recurse, LOCKMODE lockmode)
{
List *wqueue = NIL;
ListCell *lcmd;
/* Phase 1: preliminary examination of commands, create work queue */ foreach(lcmd, cmds)
{
AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
ATPrepCmd(&wqueue, rel, cmd, recurse, false, lockmode);
}
/* Close the relation, but keep lock until commit */
relation_close(rel, NoLock);
/* Phase 2: update system catalogs */
ATRewriteCatalogs(&wqueue, lockmode);
/* Phase 3: scan/rewrite tables as needed */
ATRewriteTables(&wqueue, lockmode);
}
/*
* ATPrepCmd
*
* Traffic cop for ALTER TABLE Phase 1 operations, including simple
* recursion and permission checks.
*
* Caller must have acquired appropriate lock type on relation already.
* This lock should be held until commit.
*/
static void
ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
bool recurse, bool recursing, LOCKMODE lockmode)
{
AlteredTableInfo *tab;
int pass;
/* Find or create work queue entry for this table */
tab = ATGetQueueEntry(wqueue, rel);
/*
* Copy the original subcommand for each table. This avoids conflicts
* when different child tables need to make different parse
* transformations (for example, the same column may have different column
* numbers in different children).
*/
cmd = copyObject(cmd);
/*
* Do permissions checking, recursion to child tables if needed, and any
* additional phase-1 processing needed.
*/
switch (cmd->subtype)
{
case AT_AddColumn: /* ADD COLUMN */
ATSimplePermissions(rel, false);
/* Performs own recursion */
ATPrepAddColumn(wqueue, rel, recurse, cmd, lockmode);
pass = AT_PASS_ADD_COL;
break;
case AT_AddColumnToView: /* add column via CREATE OR REPLACE
* VIEW */
ATSimplePermissions(rel, true);
/* Performs own recursion */
ATPrepAddColumn(wqueue, rel, recurse, cmd, lockmode);
pass = AT_PASS_ADD_COL;
break;
case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */
/*
* We allow defaults on views so that INSERT into a view can have
* default-ish behavior. This works because the rewriter
* substitutes default values into INSERTs before it expands
* rules. */
ATSimplePermissions(rel, true);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
/* No command-specific prep needed */
pass = cmd->def ? AT_PASS_ADD_CONSTR : AT_PASS_DROP;
break;
case AT_DropNotNull: /* ALTER COLUMN DROP NOT NULL */
ATSimplePermissions(rel, false);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
/* No command-specific prep needed */
pass = AT_PASS_DROP;
break;
case AT_SetNotNull: /* ALTER COLUMN SET NOT NULL */
ATSimplePermissions(rel, false);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
/* No command-specific prep needed */
pass = AT_PASS_ADD_CONSTR;
break;
case AT_SetStatistics: /* ALTER COLUMN SET STATISTICS */
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
/* Performs own permission checks */
ATPrepSetStatistics(rel, cmd->name, cmd->def, lockmode);
pass = AT_PASS_MISC;
break;
case AT_SetOptions: /* ALTER COLUMN SET ( options ) */
case AT_ResetOptions: /* ALTER COLUMN RESET ( options ) */
ATSimplePermissionsRelationOrIndex(rel);
/* This command never recurses */
pass = AT_PASS_MISC;
break;
case AT_SetStorage: /* ALTER COLUMN SET STORAGE */
ATSimplePermissions(rel, false);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
case AT_DropColumn: /* DROP COLUMN */
ATSimplePermissions(rel, false);
ATPrepDropColumn(rel, recurse, cmd);
/* Recursion occurs during execution phase */
pass = AT_PASS_DROP;
break;
case AT_AddIndex: /* ADD INDEX */
ATSimplePermissions(rel, false);
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_ADD_INDEX;
break;
case AT_AddConstraint: /* ADD CONSTRAINT */
ATSimplePermissions(rel, false);
/* Recursion occurs during execution phase */
/* No command-specific prep needed except saving recurse flag */
if (recurse)
cmd->subtype = AT_AddConstraintRecurse;
pass = AT_PASS_ADD_CONSTR;
break;
case AT_DropConstraint: /* DROP CONSTRAINT */
ATSimplePermissions(rel, false);
/* Recursion occurs during execution phase */
/* No command-specific prep needed except saving recurse flag */
if (recurse)
cmd->subtype = AT_DropConstraintRecurse;
pass = AT_PASS_DROP;
break;
case AT_AlterColumnType: /* ALTER COLUMN TYPE */
ATSimplePermissions(rel, false);
/* Performs own recursion */
ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd, lockmode);
pass = AT_PASS_ALTER_TYPE;
break; case AT_ChangeOwner: /* ALTER OWNER */
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
case AT_ClusterOn: /* CLUSTER ON */
case AT_DropCluster: /* SET WITHOUT CLUSTER */
ATSimplePermissions(rel, false);
/* These commands never recurse */
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
case AT_AddOids: /* SET WITH OIDS */
ATSimplePermissions(rel, false);
/* Performs own recursion */
if (!rel->rd_rel->relhasoids || recursing)
ATPrepAddOids(wqueue, rel, recurse, cmd, lockmode);
pass = AT_PASS_ADD_COL;
break;
case AT_DropOids: /* SET WITHOUT OIDS */
ATSimplePermissions(rel, false);
/* Performs own recursion */
if (rel->rd_rel->relhasoids)
{
AlterTableCmd *dropCmd = makeNode(AlterTableCmd);
dropCmd->subtype = AT_DropColumn;
dropCmd->name = pstrdup("oid");
dropCmd->behavior = cmd->behavior;
ATPrepCmd(wqueue, rel, dropCmd, recurse, false, lockmode);
}
pass = AT_PASS_DROP;
break;
case AT_SetTableSpace: /* SET TABLESPACE */
ATSimplePermissionsRelationOrIndex(rel);
/* This command never recurses */
ATPrepSetTableSpace(tab, rel, cmd->name, lockmode);
pass = AT_PASS_MISC; /* doesn't actually matter */
break;
case AT_SetRelOptions: /* SET (...) */
case AT_ResetRelOptions: /* RESET (...) */
ATSimplePermissionsRelationOrIndex(rel);
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
case AT_AddInherit: /* INHERIT */
ATSimplePermissions(rel, false);
/* This command never recurses */
ATPrepAddInherit(rel);
pass = AT_PASS_MISC;
break;
case AT_EnableTrig: /* ENABLE TRIGGER variants */
case AT_EnableAlwaysTrig:
case AT_EnableReplicaTrig:
case AT_EnableTrigAll:
case AT_EnableTrigUser:
case AT_DisableTrig: /* DISABLE TRIGGER variants */
case AT_DisableTrigAll:
case AT_DisableTrigUser:
case AT_EnableRule: /* ENABLE/DISABLE RULE variants */
case AT_EnableAlwaysRule:
case AT_EnableReplicaRule:
case AT_DisableRule:
case AT_DropInherit: /* NO INHERIT */
ATSimplePermissions(rel, false);
/* These commands never recurse */
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break; default: /* oops */
elog(ERROR, "unrecognized alter table type: %d",
(int) cmd->subtype);
pass = 0; /* keep compiler quiet */
break;
}
/* Add the subcommand to the appropriate list for phase 2 */
tab->subcmds[pass] = lappend(tab->subcmds[pass], cmd);
}
/*
* ATRewriteCatalogs
*
* Traffic cop for ALTER TABLE Phase 2 operations. Subcommands are
* dispatched in a "safe" execution order (designed to avoid unnecessary
* conflicts).
*/
static void
ATRewriteCatalogs(List **wqueue, LOCKMODE lockmode)
{
int pass;
ListCell *ltab;
/*
* We process all the tables "in parallel", one pass at a time. This is
* needed because we may have to propagate work from one table to another
* (specifically, ALTER TYPE on a foreign key's PK has to dispatch the
* re-adding of the foreign key constraint to the other table). Work can
* only be propagated into later passes, however.
*/
for (pass = 0; pass < AT_NUM_PASSES; pass++)
{
/* Go through each table that needs to be processed */
foreach(ltab, *wqueue)
{
AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
List *subcmds = tab->subcmds[pass];
Relation rel;
ListCell *lcmd;
if (subcmds == NIL)
continue;
/*
* Appropriate lock was obtained by phase 1, needn't get it again
*/
rel = relation_open(tab->relid, NoLock);
foreach(lcmd, subcmds)
ATExecCmd(wqueue, tab, rel, (AlterTableCmd *) lfirst(lcmd), lockmode);
/*
* After the ALTER TYPE pass, do cleanup work (this is not done in
* ATExecAlterColumnType since it should be done only once if
* multiple columns of a table are altered).
*/
if (pass == AT_PASS_ALTER_TYPE)
ATPostAlterTypeCleanup(wqueue, tab, lockmode);
relation_close(rel, NoLock);
}
}
/*
* Check to see if a toast table must be added, if we executed any
* subcommands that might have added a column or changed column storage.
*/
foreach(ltab, *wqueue)
{ AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
if (tab->relkind == RELKIND_RELATION &&
(tab->subcmds[AT_PASS_ADD_COL] ||
tab->subcmds[AT_PASS_ALTER_TYPE] ||
tab->subcmds[AT_PASS_COL_ATTRS]))
AlterTableCreateToastTable(tab->relid, (Datum) 0);
}
}
/*
* ATExecCmd: dispatch a subcommand to appropriate execution routine
*/
static void
ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
AlterTableCmd *cmd, LOCKMODE lockmode)
{
switch (cmd->subtype)
{
case AT_AddColumn: /* ADD COLUMN */
case AT_AddColumnToView: /* add column via CREATE OR REPLACE
* VIEW */
ATExecAddColumn(tab, rel, (ColumnDef *) cmd->def, false, lockmode);
break;
case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */
ATExecColumnDefault(rel, cmd->name, cmd->def, lockmode);
break;
case AT_DropNotNull: /* ALTER COLUMN DROP NOT NULL */
ATExecDropNotNull(rel, cmd->name, lockmode);
break;
case AT_SetNotNull: /* ALTER COLUMN SET NOT NULL */
ATExecSetNotNull(tab, rel, cmd->name, lockmode);
break;
case AT_SetStatistics: /* ALTER COLUMN SET STATISTICS */
ATExecSetStatistics(rel, cmd->name, cmd->def, lockmode);
break;
case AT_SetOptions: /* ALTER COLUMN SET ( options ) */
ATExecSetOptions(rel, cmd->name, cmd->def, false, lockmode);
break;
case AT_ResetOptions: /* ALTER COLUMN RESET ( options ) */
ATExecSetOptions(rel, cmd->name, cmd->def, true, lockmode);
break;
case AT_SetStorage: /* ALTER COLUMN SET STORAGE */
ATExecSetStorage(rel, cmd->name, cmd->def, lockmode);
break;
case AT_DropColumn: /* DROP COLUMN */
ATExecDropColumn(wqueue, rel, cmd->name,
cmd->behavior, false, false, cmd->missing_ok, lockmode);
break;
case AT_DropColumnRecurse: /* DROP COLUMN with recursion */
ATExecDropColumn(wqueue, rel, cmd->name,
cmd->behavior, true, false, cmd->missing_ok, lockmode);
break;
case AT_AddIndex: /* ADD INDEX */
ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, false, lockmode);
break;
case AT_ReAddIndex: /* ADD INDEX */
ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, true, lockmode);
break;
case AT_AddConstraint: /* ADD CONSTRAINT */
ATExecAddConstraint(wqueue, tab, rel, (Constraint *) cmd->def,
false, lockmode);
break;
case AT_AddConstraintRecurse: /* ADD CONSTRAINT with recursion */
ATExecAddConstraint(wqueue, tab, rel, (Constraint *) cmd->def,
true, lockmode);
break;
case AT_DropConstraint: /* DROP CONSTRAINT */
ATExecDropConstraint(rel, cmd->name, cmd->behavior,
false, false, cmd->missing_ok, lockmode);
break;
case AT_DropConstraintRecurse: /* DROP CONSTRAINT with recursion */
ATExecDropConstraint(rel, cmd->name, cmd->behavior,
true, false,
cmd->missing_ok, lockmode);
break;
case AT_AlterColumnType: /* ALTER COLUMN TYPE */
ATExecAlterColumnType(tab, rel, cmd->name, (TypeName *) cmd->def, lockmode);
break;
case AT_ChangeOwner: /* ALTER OWNER */
ATExecChangeOwner(RelationGetRelid(rel),
get_role_oid(cmd->name, false),
false, lockmode);
break;
case AT_ClusterOn: /* CLUSTER ON */
ATExecClusterOn(rel, cmd->name, lockmode);
break;
case AT_DropCluster: /* SET WITHOUT CLUSTER */
ATExecDropCluster(rel, lockmode);
break;
case AT_AddOids: /* SET WITH OIDS */
/* Use the ADD COLUMN code, unless prep decided to do nothing */
if (cmd->def != NULL)
ATExecAddColumn(tab, rel, (ColumnDef *) cmd->def, true, lockmode);
break;
case AT_DropOids: /* SET WITHOUT OIDS */
/*
* Nothing to do here; we'll have generated a DropColumn
* subcommand to do the real work
*/
break;
case AT_SetTableSpace: /* SET TABLESPACE */
/*
* Nothing to do here; Phase 3 does the work
*/
break;
case AT_SetRelOptions: /* SET (...) */
ATExecSetRelOptions(rel, (List *) cmd->def, false, lockmode);
break;
case AT_ResetRelOptions: /* RESET (...) */
ATExecSetRelOptions(rel, (List *) cmd->def, true, lockmode);
break;
case AT_EnableTrig: /* ENABLE TRIGGER name */
ATExecEnableDisableTrigger(rel, cmd->name,
TRIGGER_FIRES_ON_ORIGIN, false, lockmode);
break;
case AT_EnableAlwaysTrig: /* ENABLE ALWAYS TRIGGER name */
ATExecEnableDisableTrigger(rel, cmd->name,
TRIGGER_FIRES_ALWAYS, false, lockmode);
break;
case AT_EnableReplicaTrig: /* ENABLE REPLICA TRIGGER name */
ATExecEnableDisableTrigger(rel, cmd->name,
TRIGGER_FIRES_ON_REPLICA, false, lockmode);
break;
case AT_DisableTrig: /* DISABLE TRIGGER name */
ATExecEnableDisableTrigger(rel, cmd->name,
TRIGGER_DISABLED, false, lockmode);
break;
case AT_EnableTrigAll: /* ENABLE TRIGGER ALL */
ATExecEnableDisableTrigger(rel, NULL,
TRIGGER_FIRES_ON_ORIGIN, false, lockmode);
break;
case AT_DisableTrigAll: /* DISABLE TRIGGER ALL */
ATExecEnableDisableTrigger(rel, NULL,
TRIGGER_DISABLED, false, lockmode);
break; case AT_EnableTrigUser: /* ENABLE TRIGGER USER */
ATExecEnableDisableTrigger(rel, NULL,
TRIGGER_FIRES_ON_ORIGIN, true, lockmode);
break;
case AT_DisableTrigUser: /* DISABLE TRIGGER USER */
ATExecEnableDisableTrigger(rel, NULL,
TRIGGER_DISABLED, true, lockmode);
break;
case AT_EnableRule: /* ENABLE RULE name */
ATExecEnableDisableRule(rel, cmd->name,
RULE_FIRES_ON_ORIGIN, lockmode);
break;
case AT_EnableAlwaysRule: /* ENABLE ALWAYS RULE name */
ATExecEnableDisableRule(rel, cmd->name,
RULE_FIRES_ALWAYS, lockmode);
break;
case AT_EnableReplicaRule: /* ENABLE REPLICA RULE name */
ATExecEnableDisableRule(rel, cmd->name,
RULE_FIRES_ON_REPLICA, lockmode);
break;
case AT_DisableRule: /* DISABLE RULE name */
ATExecEnableDisableRule(rel, cmd->name,
RULE_DISABLED, lockmode);
break;
case AT_AddInherit:
ATExecAddInherit(rel, (RangeVar *) cmd->def, lockmode);
break;
case AT_DropInherit:
ATExecDropInherit(rel, (RangeVar *) cmd->def, lockmode);
break;
default: /* oops */
elog(ERROR, "unrecognized alter table type: %d",
(int) cmd->subtype);
break;
}
/*
* Bump the command counter to ensure the next subcommand in the sequence
* can see the changes so far
*/
CommandCounterIncrement();
}
/*
* ATRewriteTables: ALTER TABLE phase 3
*/
static void
ATRewriteTables(List **wqueue, LOCKMODE lockmode)
{
ListCell *ltab;
/* Go through each table that needs to be checked or rewritten */
foreach(ltab, *wqueue)
{
AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
/*
* We only need to rewrite the table if at least one column needs to
* be recomputed, or we are adding/removing the OID column.
*/
if (tab->newvals != NIL || tab->new_changeoids)
{
/* Build a temporary relation and copy data */
Relation OldHeap;
Oid OIDNewHeap;
Oid NewTableSpace;
OldHeap = heap_open(tab->relid, NoLock);
/*
* We don't support rewriting of system catalogs; there are too
* many corner cases and too little benefit. In particular this
* is certainly not going to work for mapped catalogs.
*/
if (IsSystemRelation(OldHeap))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot rewrite system relation \"%s\"",
RelationGetRelationName(OldHeap))));
/*
* Don't allow rewrite on temp tables of other backends ... their
* local buffer manager is not going to cope.
*/
if (RELATION_IS_OTHER_TEMP(OldHeap))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot rewrite temporary tables of other sessions")));
/*
* Select destination tablespace (same as original unless user
* requested a change)
*/
if (tab->newTableSpace)
NewTableSpace = tab->newTableSpace;
else
NewTableSpace = OldHeap->rd_rel->reltablespace;
heap_close(OldHeap, NoLock);
/* Create transient table that will receive the modified data */
OIDNewHeap = make_new_heap(tab->relid, NewTableSpace);
/*
* Copy the heap data into the new table with the desired
* modifications, and test the current data within the table
* against new constraints generated by ALTER TABLE commands.
*/
ATRewriteTable(tab, OIDNewHeap, lockmode);
/*
* Swap the physical files of the old and new heaps, then rebuild
* indexes and discard the new heap. We can use RecentXmin for
* the table's new relfrozenxid because we rewrote all the tuples
* in ATRewriteTable, so no older Xid remains in the table. Also,
* we never try to swap toast tables by content, since we have no
* interest in letting this code work on system catalogs.
*/
finish_heap_swap(tab->relid, OIDNewHeap, false, false, RecentXmin);
}
else
{
/*
* Test the current data within the table against new constraints
* generated by ALTER TABLE commands, but don't rebuild data.
*/
if (tab->constraints != NIL || tab->new_notnull)
ATRewriteTable(tab, InvalidOid, lockmode);
/*
* If we had SET TABLESPACE but no reason to reconstruct tuples,
* just do a block-by-block copy.
*/
if (tab->newTableSpace)
ATExecSetTableSpace(tab->relid, tab->newTableSpace, lockmode);
}
}
/*
* Foreign key constraints are checked in a final pass, since (a) it's
* generally best to examine each one separately, and (b) it's at least
* theoretically possible that we have changed both relations of the
* foreign key, and we'd better have finished both rewrites before we try
* to read the tables.
*/
foreach(ltab, *wqueue)
{
AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
Relation rel = NULL;
ListCell *lcon;
foreach(lcon, tab->constraints)
{
NewConstraint *con = lfirst(lcon);
if (con->contype == CONSTR_FOREIGN)
{
Constraint *fkconstraint = (Constraint *) con->qual;
Relation refrel;
if (rel == NULL)
/* Long since locked, no need for another */
rel = heap_open(tab->relid, NoLock);
/*
* We're adding a trigger to both tables, so the lock level
* here should sensibly reflect that.
*/
refrel = heap_open(con->refrelid, ShareRowExclusiveLock);
validateForeignKeyConstraint(fkconstraint, rel, refrel,
con->refindid,
con->conid);
heap_close(refrel, NoLock);
}
}
if (rel)
heap_close(rel, NoLock);
}
}
/*
* ATRewriteTable: scan or rewrite one table
*
* OIDNewHeap is InvalidOid if we don't need to rewrite
*/
static void
ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
{
Relation oldrel;
Relation newrel;
TupleDesc oldTupDesc;
TupleDesc newTupDesc;
bool needscan = false;
List *notnull_attrs;
int i;
ListCell *l;
EState *estate;
CommandId mycid;
BulkInsertState bistate;
int hi_options;
/*
* Open the relation(s). We have surely already locked the existing
* table.
*/ oldrel = heap_open(tab->relid, NoLock);
oldTupDesc = tab->oldDesc;
newTupDesc = RelationGetDescr(oldrel); /* includes all mods */
if (OidIsValid(OIDNewHeap))
newrel = heap_open(OIDNewHeap, lockmode);
else
newrel = NULL;
/*
* Prepare a BulkInsertState and options for heap_insert. Because we're
* building a new heap, we can skip WAL-logging and fsync it to disk at
* the end instead (unless WAL-logging is required for archiving or
* streaming replication). The FSM is empty too, so don't bother using it.
*/
if (newrel)
{
mycid = GetCurrentCommandId(true);
bistate = GetBulkInsertState();
hi_options = HEAP_INSERT_SKIP_FSM;
if (!XLogIsNeeded())
hi_options |= HEAP_INSERT_SKIP_WAL;
}
else
{
/* keep compiler quiet about using these uninitialized */
mycid = 0;
bistate = NULL;
hi_options = 0;
}
/*
* If we need to rewrite the table, the operation has to be propagated to
* tables that use this table's rowtype as a column type.
*
* (Eventually this will probably become true for scans as well, but at
* the moment a composite type does not enforce any constraints, so it's
* not necessary/appropriate to enforce them just during ALTER.)
*/
if (newrel)
find_composite_type_dependencies(oldrel->rd_rel->reltype,
RelationGetRelationName(oldrel),
NULL);
/*
* Generate the constraint and default execution states
*/
estate = CreateExecutorState();
/* Build the needed expression execution states */
foreach(l, tab->constraints)
{
NewConstraint *con = lfirst(l);
switch (con->contype)
{
case CONSTR_CHECK:
needscan = true;
con->qualstate = (List *)
ExecPrepareExpr((Expr *) con->qual, estate);
break;
case CONSTR_FOREIGN:
/* Nothing to do here */
break;
default:
elog(ERROR, "unrecognized constraint type: %d",
(int) con->contype);
} }
foreach(l, tab->newvals)
{
NewColumnValue *ex = lfirst(l);
ex->exprstate = ExecPrepareExpr((Expr *) ex->expr, estate);
}
notnull_attrs = NIL;
if (newrel || tab->new_notnull)
{
/*
* If we are rebuilding the tuples OR if we added any new NOT NULL
* constraints, check all not-null constraints. This is a bit of
* overkill but it minimizes risk of bugs, and heap_attisnull is a
* pretty cheap test anyway.
*/
for (i = 0; i < newTupDesc->natts; i++)
{
if (newTupDesc->attrs[i]->attnotnull &&
!newTupDesc->attrs[i]->attisdropped)
notnull_attrs = lappend_int(notnull_attrs, i);
}
if (notnull_attrs)
needscan = true;
}
if (newrel || needscan)
{
ExprContext *econtext;
Datum *values;
bool *isnull;
TupleTableSlot *oldslot;
TupleTableSlot *newslot;
HeapScanDesc scan;
HeapTuple tuple;
MemoryContext oldCxt;
List *dropped_attrs = NIL;
ListCell *lc;
econtext = GetPerTupleExprContext(estate);
/*
* Make tuple slots for old and new tuples. Note that even when the
* tuples are the same, the tupDescs might not be (consider ADD COLUMN
* without a default).
*/
oldslot = MakeSingleTupleTableSlot(oldTupDesc);
newslot = MakeSingleTupleTableSlot(newTupDesc);
/* Preallocate values/isnull arrays */
i = Max(newTupDesc->natts, oldTupDesc->natts);
values = (Datum *) palloc(i * sizeof(Datum));
isnull = (bool *) palloc(i * sizeof(bool));
memset(values, 0, i * sizeof(Datum));
memset(isnull, true, i * sizeof(bool));
/*
* Any attributes that are dropped according to the new tuple
* descriptor can be set to NULL. We precompute the list of dropped
* attributes to avoid needing to do so in the per-tuple loop.
*/
for (i = 0; i < newTupDesc->natts; i++)
{
if (newTupDesc->attrs[i]->attisdropped)
dropped_attrs = lappend_int(dropped_attrs, i);
}
/* * Scan through the rows, generating a new row if needed and then
* checking all the constraints.
*/
scan = heap_beginscan(oldrel, SnapshotNow, 0, NULL);
/*
* Switch to per-tuple memory context and reset it for each tuple
* produced, so we don't leak memory.
*/
oldCxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
if (newrel)
{
Oid tupOid = InvalidOid;
/* Extract data from old tuple */
heap_deform_tuple(tuple, oldTupDesc, values, isnull);
if (oldTupDesc->tdhasoid)
tupOid = HeapTupleGetOid(tuple);
/* Set dropped attributes to null in new tuple */
foreach(lc, dropped_attrs)
isnull[lfirst_int(lc)] = true;
/*
* Process supplied expressions to replace selected columns.
* Expression inputs come from the old tuple.
*/
ExecStoreTuple(tuple, oldslot, InvalidBuffer, false);
econtext->ecxt_scantuple = oldslot;
foreach(l, tab->newvals)
{
NewColumnValue *ex = lfirst(l);
values[ex->attnum - 1] = ExecEvalExpr(ex->exprstate,
econtext,
&isnull[ex->attnum - 1],
NULL);
}
/*
* Form the new tuple. Note that we don't explicitly pfree it,
* since the per-tuple memory context will be reset shortly.
*/
tuple = heap_form_tuple(newTupDesc, values, isnull);
/* Preserve OID, if any */
if (newTupDesc->tdhasoid)
HeapTupleSetOid(tuple, tupOid);
}
/* Now check any constraints on the possibly-changed tuple */
ExecStoreTuple(tuple, newslot, InvalidBuffer, false);
econtext->ecxt_scantuple = newslot;
foreach(l, notnull_attrs)
{
int attn = lfirst_int(l);
if (heap_attisnull(tuple, attn + 1))
ereport(ERROR,
(errcode(ERRCODE_NOT_NULL_VIOLATION),
errmsg("column \"%s\" contains null values",
NameStr(newTupDesc->attrs[attn]->attname))));
}
foreach(l, tab->constraints) {
NewConstraint *con = lfirst(l);
switch (con->contype)
{
case CONSTR_CHECK:
if (!ExecQual(con->qualstate, econtext, true))
ereport(ERROR,
(errcode(ERRCODE_CHECK_VIOLATION),
errmsg("check constraint \"%s\" is violated by some row",
con->name)));
break;
case CONSTR_FOREIGN:
/* Nothing to do here */
break;
default:
elog(ERROR, "unrecognized constraint type: %d",
(int) con->contype);
}
}
/* Write the tuple out to the new relation */
if (newrel)
heap_insert(newrel, tuple, mycid, hi_options, bistate);
ResetExprContext(econtext);
CHECK_FOR_INTERRUPTS();
}
MemoryContextSwitchTo(oldCxt);
heap_endscan(scan);
ExecDropSingleTupleTableSlot(oldslot);
ExecDropSingleTupleTableSlot(newslot);
}
FreeExecutorState(estate);
heap_close(oldrel, NoLock);
if (newrel)
{
FreeBulkInsertState(bistate);
/* If we skipped writing WAL, then we need to sync the heap. */
if (hi_options & HEAP_INSERT_SKIP_WAL)
heap_sync(newrel);
heap_close(newrel, NoLock);
}
}
/*
* ATGetQueueEntry: find or create an entry in the ALTER TABLE work queue
*/
static AlteredTableInfo *
ATGetQueueEntry(List **wqueue, Relation rel)
{
Oid relid = RelationGetRelid(rel);
AlteredTableInfo *tab;
ListCell *ltab;
foreach(ltab, *wqueue)
{
tab = (AlteredTableInfo *) lfirst(ltab);
if (tab->relid == relid)
return tab;
}
/* * Not there, so add it. Note that we make a copy of the relation's
* existing descriptor before anything interesting can happen to it.
*/
tab = (AlteredTableInfo *) palloc0(sizeof(AlteredTableInfo));
tab->relid = relid;
tab->relkind = rel->rd_rel->relkind;
tab->oldDesc = CreateTupleDescCopy(RelationGetDescr(rel));
*wqueue = lappend(*wqueue, tab);
return tab;
}
/*
* ATSimplePermissions
*
* - Ensure that it is a relation (or possibly a view)
* - Ensure this user is the owner
* - Ensure that it is not a system table
*/
static void
ATSimplePermissions(Relation rel, bool allowView)
{
if (rel->rd_rel->relkind != RELKIND_RELATION)
{
if (allowView)
{
if (rel->rd_rel->relkind != RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or view",
RelationGetRelationName(rel))));
}
else
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
RelationGetRelationName(rel))));
}
/* Permissions checks */
if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(rel));
if (!allowSystemTableMods && IsSystemRelation(rel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(rel))));
}
/*
* ATSimplePermissionsRelationOrIndex
*
* - Ensure that it is a relation or an index
* - Ensure this user is the owner
* - Ensure that it is not a system table
*/
static void
ATSimplePermissionsRelationOrIndex(Relation rel)
{
if (rel->rd_rel->relkind != RELKIND_RELATION &&
rel->rd_rel->relkind != RELKIND_INDEX)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or index",
RelationGetRelationName(rel))));
/* Permissions checks */ if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(rel));
if (!allowSystemTableMods && IsSystemRelation(rel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(rel))));
}
/*
* ATSimpleRecursion
*
* Simple table recursion sufficient for most ALTER TABLE operations.
* All direct and indirect children are processed in an unspecified order.
* Note that if a child inherits from the original table via multiple
* inheritance paths, it will be visited just once.
*/
static void
ATSimpleRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd, bool recurse, LOCKMODE lockmode)
{
/*
* Propagate to children if desired. Non-table relations never have
* children, so no need to search in that case.
*/
if (recurse && rel->rd_rel->relkind == RELKIND_RELATION)
{
Oid relid = RelationGetRelid(rel);
ListCell *child;
List *children;
children = find_all_inheritors(relid, lockmode, NULL);
/*
* find_all_inheritors does the recursive search of the inheritance
* hierarchy, so all we have to do is process all of the relids in the
* list that it returns.
*/
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
Relation childrel;
if (childrelid == relid)
continue;
/* find_all_inheritors already got lock */
childrel = relation_open(childrelid, NoLock);
CheckTableNotInUse(childrel, "ALTER TABLE");
ATPrepCmd(wqueue, childrel, cmd, false, true, lockmode);
relation_close(childrel, NoLock);
}
}
}
/*
* ATOneLevelRecursion
*
* Here, we visit only direct inheritance children. It is expected that
* the command's prep routine will recurse again to find indirect children.
* When using this technique, a multiply-inheriting child will be visited
* multiple times.
*/
static void
ATOneLevelRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd, LOCKMODE lockmode)
{
Oid relid = RelationGetRelid(rel);
ListCell *child; List *children;
children = find_inheritance_children(relid, lockmode);
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
Relation childrel;
/* find_inheritance_children already got lock */
childrel = relation_open(childrelid, NoLock);
CheckTableNotInUse(childrel, "ALTER TABLE");
ATPrepCmd(wqueue, childrel, cmd, true, true, lockmode);
relation_close(childrel, NoLock);
}
}
/*
* find_composite_type_dependencies
*
* Check to see if a composite type is being used as a column in some
* other table (possibly nested several levels deep in composite types!).
* Eventually, we'd like to propagate the check or rewrite operation
* into other such tables, but for now, just error out if we find any.
*
* Caller should provide either a table name or a type name (not both) to
* report in the error message, if any.
*
* We assume that functions and views depending on the type are not reasons
* to reject the ALTER. (How safe is this really?)
*/
void
find_composite_type_dependencies(Oid typeOid,
const char *origTblName,
const char *origTypeName)
{
Relation depRel;
ScanKeyData key[2];
SysScanDesc depScan;
HeapTuple depTup;
Oid arrayOid;
/*
* We scan pg_depend to find those things that depend on the rowtype. (We
* assume we can ignore refobjsubid for a rowtype.)
*/
depRel = heap_open(DependRelationId, AccessShareLock);
ScanKeyInit(&key[0],
Anum_pg_depend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(TypeRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(typeOid));
depScan = systable_beginscan(depRel, DependReferenceIndexId, true,
SnapshotNow, 2, key);
while (HeapTupleIsValid(depTup = systable_getnext(depScan)))
{
Form_pg_depend pg_depend = (Form_pg_depend) GETSTRUCT(depTup);
Relation rel;
Form_pg_attribute att;
/* Ignore dependees that aren't user columns of relations */
/* (we assume system columns are never of rowtypes) */
if (pg_depend->classid != RelationRelationId || pg_depend->objsubid <= 0)
continue;
rel = relation_open(pg_depend->objid, AccessShareLock);
att = rel->rd_att->attrs[pg_depend->objsubid - 1];
if (rel->rd_rel->relkind == RELKIND_RELATION)
{
if (origTblName)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter table \"%s\" because column \"%s\".\"%s\" uses its rowtype",
origTblName,
RelationGetRelationName(rel),
NameStr(att->attname))));
else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type \"%s\" because column \"%s\".\"%s\" uses it",
origTypeName,
RelationGetRelationName(rel),
NameStr(att->attname))));
}
else if (OidIsValid(rel->rd_rel->reltype))
{
/*
* A view or composite type itself isn't a problem, but we must
* recursively check for indirect dependencies via its rowtype.
*/
find_composite_type_dependencies(rel->rd_rel->reltype,
origTblName, origTypeName);
}
relation_close(rel, AccessShareLock);
}
systable_endscan(depScan);
relation_close(depRel, AccessShareLock);
/*
* If there's an array type for the rowtype, must check for uses of it,
* too.
*/
arrayOid = get_array_type(typeOid);
if (OidIsValid(arrayOid))
find_composite_type_dependencies(arrayOid, origTblName, origTypeName);
}
/*
* ALTER TABLE ADD COLUMN
*
* Adds an additional attribute to a relation making the assumption that
* CHECK, NOT NULL, and FOREIGN KEY constraints will be removed from the
* AT_AddColumn AlterTableCmd by parse_utilcmd.c and added as independent
* AlterTableCmd's.
*/
static void
ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
AlterTableCmd *cmd, LOCKMODE lockmode)
{
if (rel->rd_rel->reloftype)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot add column to typed table")));
/*
* Recurse to add the column to child classes, if requested.
* * We must recurse one level at a time, so that multiply-inheriting
* children are visited the right number of times and end up with the
* right attinhcount.
*/
if (recurse)
{
AlterTableCmd *childCmd = copyObject(cmd);
ColumnDef *colDefChild = (ColumnDef *) childCmd->def;
/* Child should see column as singly inherited */
colDefChild->inhcount = 1;
colDefChild->is_local = false;
ATOneLevelRecursion(wqueue, rel, childCmd, lockmode);
}
else
{
/*
* If we are told not to recurse, there had better not be any child
* tables; else the addition would put them out of step.
*/
if (find_inheritance_children(RelationGetRelid(rel), NoLock) != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column must be added to child tables too")));
}
}
static void
ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
ColumnDef *colDef, bool isOid, LOCKMODE lockmode)
{
Oid myrelid = RelationGetRelid(rel);
Relation pgclass,
attrdesc;
HeapTuple reltup;
FormData_pg_attribute attribute;
int newattnum;
char relkind;
HeapTuple typeTuple;
Oid typeOid;
int32 typmod;
Form_pg_type tform;
Expr *defval;
attrdesc = heap_open(AttributeRelationId, RowExclusiveLock);
/*
* Are we adding the column to a recursion child? If so, check whether to
* merge with an existing definition for the column.
*/
if (colDef->inhcount > 0)
{
HeapTuple tuple;
/* Does child already have a column by this name? */
tuple = SearchSysCacheCopyAttName(myrelid, colDef->colname);
if (HeapTupleIsValid(tuple))
{
Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
Oid ctypeId;
int32 ctypmod;
/* Child column must match by type */
ctypeId = typenameTypeId(NULL, colDef->typeName, &ctypmod);
if (ctypeId != childatt->atttypid ||
ctypmod != childatt->atttypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table \"%s\" has different type for column \"%s\"", RelationGetRelationName(rel), colDef->colname)));
/* If it's OID, child column must actually be OID */
if (isOid && childatt->attnum != ObjectIdAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table \"%s\" has a conflicting \"%s\" column",
RelationGetRelationName(rel), colDef->colname)));
/* Bump the existing child att's inhcount */
childatt->attinhcount++;
simple_heap_update(attrdesc, &tuple->t_self, tuple);
CatalogUpdateIndexes(attrdesc, tuple);
heap_freetuple(tuple);
/* Inform the user about the merge */
ereport(NOTICE,
(errmsg("merging definition of column \"%s\" for child \"%s\"",
colDef->colname, RelationGetRelationName(rel))));
heap_close(attrdesc, RowExclusiveLock);
return;
}
}
pgclass = heap_open(RelationRelationId, RowExclusiveLock);
reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(myrelid));
if (!HeapTupleIsValid(reltup))
elog(ERROR, "cache lookup failed for relation %u", myrelid);
relkind = ((Form_pg_class) GETSTRUCT(reltup))->relkind;
/*
* this test is deliberately not attisdropped-aware, since if one tries to
* add a column matching a dropped column name, it's gonna fail anyway.
*/
if (SearchSysCacheExists2(ATTNAME,
ObjectIdGetDatum(myrelid),
PointerGetDatum(colDef->colname)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" of relation \"%s\" already exists",
colDef->colname, RelationGetRelationName(rel))));
/* Determine the new attribute's number */
if (isOid)
newattnum = ObjectIdAttributeNumber;
else
{
newattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts + 1;
if (newattnum > MaxHeapAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("tables can have at most %d columns",
MaxHeapAttributeNumber)));
}
typeTuple = typenameType(NULL, colDef->typeName, &typmod);
tform = (Form_pg_type) GETSTRUCT(typeTuple);
typeOid = HeapTupleGetOid(typeTuple);
/* make sure datatype is legal for a column */
CheckAttributeType(colDef->colname, typeOid, false);
/* construct new attribute's pg_attribute entry */
attribute.attrelid = myrelid;
namestrcpy(&(attribute.attname), colDef->colname);
attribute.atttypid = typeOid;
attribute.attstattarget = (newattnum > 0) ? -1 : 0; attribute.attlen = tform->typlen;
attribute.attcacheoff = -1;
attribute.atttypmod = typmod;
attribute.attnum = newattnum;
attribute.attbyval = tform->typbyval;
attribute.attndims = list_length(colDef->typeName->arrayBounds);
attribute.attstorage = tform->typstorage;
attribute.attalign = tform->typalign;
attribute.attnotnull = colDef->is_not_null;
attribute.atthasdef = false;
attribute.attisdropped = false;
attribute.attislocal = colDef->is_local;
attribute.attinhcount = colDef->inhcount;
/* attribute.attacl is handled by InsertPgAttributeTuple */
ReleaseSysCache(typeTuple);
InsertPgAttributeTuple(attrdesc, &attribute, NULL);
heap_close(attrdesc, RowExclusiveLock);
/*
* Update pg_class tuple as appropriate
*/
if (isOid)
((Form_pg_class) GETSTRUCT(reltup))->relhasoids = true;
else
((Form_pg_class) GETSTRUCT(reltup))->relnatts = newattnum;
simple_heap_update(pgclass, &reltup->t_self, reltup);
/* keep catalog indexes current */
CatalogUpdateIndexes(pgclass, reltup);
heap_freetuple(reltup);
heap_close(pgclass, RowExclusiveLock);
/* Make the attribute's catalog entry visible */
CommandCounterIncrement();
/*
* Store the DEFAULT, if any, in the catalogs
*/
if (colDef->raw_default)
{
RawColumnDefault *rawEnt;
rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
rawEnt->attnum = attribute.attnum;
rawEnt->raw_default = copyObject(colDef->raw_default);
/*
* This function is intended for CREATE TABLE, so it processes a
* _list_ of defaults, but we just do one.
*/
AddRelationNewConstraints(rel, list_make1(rawEnt), NIL, false, true);
/* Make the additional catalog changes visible */
CommandCounterIncrement();
}
/*
* Tell Phase 3 to fill in the default expression, if there is one.
*
* If there is no default, Phase 3 doesn't have to do anything, because
* that effectively means that the default is NULL. The heap tuple access
* routines always check for attnum > # of attributes in tuple, and return
* NULL if so, so without any modification of the tuple data we will get
* the effect of NULL values in the new column. *
* An exception occurs when the new column is of a domain type: the domain
* might have a NOT NULL constraint, or a check constraint that indirectly
* rejects nulls. If there are any domain constraints then we construct
* an explicit NULL default value that will be passed through
* CoerceToDomain processing. (This is a tad inefficient, since it causes
* rewriting the table which we really don't have to do, but the present
* design of domain processing doesn't offer any simple way of checking
* the constraints more directly.)
*
* Note: we use build_column_default, and not just the cooked default
* returned by AddRelationNewConstraints, so that the right thing happens
* when a datatype's default applies.
*
* We skip this step completely for views. For a view, we can only get
* here from CREATE OR REPLACE VIEW, which historically doesn't set up
* defaults, not even for domain-typed columns. And in any case we
* mustn't invoke Phase 3 on a view, since it has no storage.
*/
if (relkind != RELKIND_VIEW && attribute.attnum > 0)
{
defval = (Expr *) build_column_default(rel, attribute.attnum);
if (!defval && GetDomainConstraints(typeOid) != NIL)
{
Oid baseTypeId;
int32 baseTypeMod;
baseTypeMod = typmod;
baseTypeId = getBaseTypeAndTypmod(typeOid, &baseTypeMod);
defval = (Expr *) makeNullConst(baseTypeId, baseTypeMod);
defval = (Expr *) coerce_to_target_type(NULL,
(Node *) defval,
baseTypeId,
typeOid,
typmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST,
-1);
if (defval == NULL) /* should not happen */
elog(ERROR, "failed to coerce base type to domain");
}
if (defval)
{
NewColumnValue *newval;
newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
newval->attnum = attribute.attnum;
newval->expr = defval;
tab->newvals = lappend(tab->newvals, newval);
}
/*
* If the new column is NOT NULL, tell Phase 3 it needs to test that.
* (Note we don't do this for an OID column. OID will be marked not
* null, but since it's filled specially, there's no need to test
* anything.)
*/
tab->new_notnull |= colDef->is_not_null;
}
/*
* If we are adding an OID column, we have to tell Phase 3 to rewrite the
* table to fix that.
*/
if (isOid)
tab->new_changeoids = true;
/*
* Add needed dependency entries for the new column.
*/
add_column_datatype_dependency(myrelid, newattnum, attribute.atttypid);
}
/*
* Install a column's dependency on its datatype.
*/
static void
add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid)
{
ObjectAddress myself,
referenced;
myself.classId = RelationRelationId;
myself.objectId = relid;
myself.objectSubId = attnum;
referenced.classId = TypeRelationId;
referenced.objectId = typid;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
}
/*
* ALTER TABLE SET WITH OIDS
*
* Basically this is an ADD COLUMN for the special OID column. We have
* to cons up a ColumnDef node because the ADD COLUMN code needs one.
*/
static void
ATPrepAddOids(List **wqueue, Relation rel, bool recurse, AlterTableCmd *cmd, LOCKMODE lockmode)
{
/* If we're recursing to a child table, the ColumnDef is already set up */
if (cmd->def == NULL)
{
ColumnDef *cdef = makeNode(ColumnDef);
cdef->colname = pstrdup("oid");
cdef->typeName = makeTypeNameFromOid(OIDOID, -1);
cdef->inhcount = 0;
cdef->is_local = true;
cdef->is_not_null = true;
cdef->storage = 0;
cmd->def = (Node *) cdef;
}
ATPrepAddColumn(wqueue, rel, recurse, cmd, lockmode);
}
/*
* ALTER TABLE ALTER COLUMN DROP NOT NULL
*/
static void
ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
{
HeapTuple tuple;
AttrNumber attnum;
Relation attr_rel;
List *indexoidlist;
ListCell *indexoidscan;
/*
* lookup the attribute
*/
attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
/* Prevent them from altering a system attribute */
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/*
* Check that the attribute is not in a primary key
*/
/* Loop over all indexes on the relation */
indexoidlist = RelationGetIndexList(rel);
foreach(indexoidscan, indexoidlist)
{
Oid indexoid = lfirst_oid(indexoidscan);
HeapTuple indexTuple;
Form_pg_index indexStruct;
int i;
indexTuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexoid));
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexoid);
indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
/* If the index is not a primary key, skip the check */
if (indexStruct->indisprimary)
{
/*
* Loop over each attribute in the primary key and see if it
* matches the to-be-altered attribute
*/
for (i = 0; i < indexStruct->indnatts; i++)
{
if (indexStruct->indkey.values[i] == attnum)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column \"%s\" is in a primary key",
colName)));
}
}
ReleaseSysCache(indexTuple);
}
list_free(indexoidlist);
/*
* Okay, actually perform the catalog change ... if needed
*/
if (((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
{
((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = FALSE;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
}
heap_close(attr_rel, RowExclusiveLock);
}
/*
* ALTER TABLE ALTER COLUMN SET NOT NULL
*/
static void
ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
const char *colName, LOCKMODE lockmode)
{
HeapTuple tuple;
AttrNumber attnum;
Relation attr_rel;
/*
* lookup the attribute
*/
attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
/* Prevent them from altering a system attribute */
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/*
* Okay, actually perform the catalog change ... if needed
*/
if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
{
((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = TRUE;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
/* Tell Phase 3 it needs to test the constraint */
tab->new_notnull = true;
}
heap_close(attr_rel, RowExclusiveLock);
}
/*
* ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
*/
static void
ATExecColumnDefault(Relation rel, const char *colName,
Node *newDefault, LOCKMODE lockmode)
{
AttrNumber attnum;
/*
* get the number of the attribute
*/
attnum = get_attnum(RelationGetRelid(rel), colName);
if (attnum == InvalidAttrNumber)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
/* Prevent them from altering a system attribute */
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/*
* Remove any old default for the column. We use RESTRICT here for
* safety, but at present we do not expect anything to depend on the
* default.
*/
RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, false);
if (newDefault)
{
/* SET DEFAULT */
RawColumnDefault *rawEnt;
rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
rawEnt->attnum = attnum;
rawEnt->raw_default = newDefault;
/*
* This function is intended for CREATE TABLE, so it processes a
* _list_ of defaults, but we just do one.
*/
AddRelationNewConstraints(rel, list_make1(rawEnt), NIL, false, true);
}
}
/*
* ALTER TABLE ALTER COLUMN SET STATISTICS
*/
static void
ATPrepSetStatistics(Relation rel, const char *colName, Node *newValue, LOCKMODE lockmode)
{
/*
* We do our own permission checking because (a) we want to allow SET
* STATISTICS on indexes (for expressional index columns), and (b) we want
* to allow SET STATISTICS on system catalogs without requiring
* allowSystemTableMods to be turned on.
*/
if (rel->rd_rel->relkind != RELKIND_RELATION &&
rel->rd_rel->relkind != RELKIND_INDEX)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or index",
RelationGetRelationName(rel))));
/* Permissions checks */
if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(rel));
}
static void
ATExecSetStatistics(Relation rel, const char *colName, Node *newValue, LOCKMODE lockmode)
{
int newtarget;
Relation attrelation;
HeapTuple tuple;
Form_pg_attribute attrtuple;
Assert(IsA(newValue, Integer));
newtarget = intVal(newValue);
/*
* Limit target to a sane range */
if (newtarget < -1)
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("statistics target %d is too low",
newtarget)));
}
else if (newtarget > 10000)
{
newtarget = 10000;
ereport(WARNING,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("lowering statistics target to %d",
newtarget)));
}
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
if (attrtuple->attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
attrtuple->attstattarget = newtarget;
simple_heap_update(attrelation, &tuple->t_self, tuple);
/* keep system catalog indexes current */
CatalogUpdateIndexes(attrelation, tuple);
heap_freetuple(tuple);
heap_close(attrelation, RowExclusiveLock);
}
static void
ATExecSetOptions(Relation rel, const char *colName, Node *options,
bool isReset, LOCKMODE lockmode)
{
Relation attrelation;
HeapTuple tuple,
newtuple;
Form_pg_attribute attrtuple;
Datum datum,
newOptions;
bool isnull;
Datum repl_val[Natts_pg_attribute];
bool repl_null[Natts_pg_attribute];
bool repl_repl[Natts_pg_attribute];
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel)))); attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
if (attrtuple->attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/* Generate new proposed attoptions (text array) */
Assert(IsA(options, List));
datum = SysCacheGetAttr(ATTNAME, tuple, Anum_pg_attribute_attoptions,
&isnull);
newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
(List *) options, NULL, NULL, false,
isReset);
/* Validate new options */
(void) attribute_reloptions(newOptions, true);
/* Build new tuple. */
memset(repl_null, false, sizeof(repl_null));
memset(repl_repl, false, sizeof(repl_repl));
if (newOptions != (Datum) 0)
repl_val[Anum_pg_attribute_attoptions - 1] = newOptions;
else
repl_null[Anum_pg_attribute_attoptions - 1] = true;
repl_repl[Anum_pg_attribute_attoptions - 1] = true;
newtuple = heap_modify_tuple(tuple, RelationGetDescr(attrelation),
repl_val, repl_null, repl_repl);
ReleaseSysCache(tuple);
/* Update system catalog. */
simple_heap_update(attrelation, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(attrelation, newtuple);
heap_freetuple(newtuple);
heap_close(attrelation, RowExclusiveLock);
}
/*
* ALTER TABLE ALTER COLUMN SET STORAGE
*/
static void
ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE lockmode)
{
char *storagemode;
char newstorage;
Relation attrelation;
HeapTuple tuple;
Form_pg_attribute attrtuple;
Assert(IsA(newValue, String));
storagemode = strVal(newValue);
if (pg_strcasecmp(storagemode, "plain") == 0)
newstorage = 'p';
else if (pg_strcasecmp(storagemode, "external") == 0)
newstorage = 'e';
else if (pg_strcasecmp(storagemode, "extended") == 0)
newstorage = 'x';
else if (pg_strcasecmp(storagemode, "main") == 0)
newstorage = 'm';
else
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid storage type \"%s\"",
storagemode)));
newstorage = 0; /* keep compiler quiet */
}
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
if (attrtuple->attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/*
* safety check: do not allow toasted storage modes unless column datatype
* is TOAST-aware.
*/
if (newstorage == 'p' || TypeIsToastable(attrtuple->atttypid))
attrtuple->attstorage = newstorage;
else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("column data type %s can only have storage PLAIN",
format_type_be(attrtuple->atttypid))));
simple_heap_update(attrelation, &tuple->t_self, tuple);
/* keep system catalog indexes current */
CatalogUpdateIndexes(attrelation, tuple);
heap_freetuple(tuple);
heap_close(attrelation, RowExclusiveLock);
}
/*
* ALTER TABLE DROP COLUMN
*
* DROP COLUMN cannot use the normal ALTER TABLE recursion mechanism,
* because we have to decide at runtime whether to recurse or not depending
* on whether attinhcount goes to zero or not. (We can't check this in a
* static pre-pass because it won't handle multiple inheritance situations
* correctly.)
*/
static void
ATPrepDropColumn(Relation rel, bool recurse, AlterTableCmd *cmd)
{
if (rel->rd_rel->reloftype)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot drop column from typed table")));
/* No command-specific prep needed except saving recurse flag */
if (recurse)
cmd->subtype = AT_DropColumnRecurse;
}
static void
ATExecDropColumn(List **wqueue, Relation rel, const char *colName,
DropBehavior behavior,
bool recurse, bool recursing,
bool missing_ok, LOCKMODE lockmode)
{
HeapTuple tuple;
Form_pg_attribute targetatt; AttrNumber attnum;
List *children;
ObjectAddress object;
/* At top level, permission check was done in ATPrepCmd, else do it */
if (recursing)
ATSimplePermissions(rel, false);
/*
* get the number of the attribute
*/
tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
{
if (!missing_ok)
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
}
else
{
ereport(NOTICE,
(errmsg("column \"%s\" of relation \"%s\" does not exist, skipping",
colName, RelationGetRelationName(rel))));
return;
}
}
targetatt = (Form_pg_attribute) GETSTRUCT(tuple);
attnum = targetatt->attnum;
/* Can't drop a system attribute, except OID */
if (attnum <= 0 && attnum != ObjectIdAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot drop system column \"%s\"",
colName)));
/* Don't drop inherited columns */
if (targetatt->attinhcount > 0 && !recursing)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot drop inherited column \"%s\"",
colName)));
ReleaseSysCache(tuple);
/*
* Propagate to children as appropriate. Unlike most other ALTER
* routines, we have to do this one level of recursion at a time; we can't
* use find_all_inheritors to do it in one pass.
*/
children = find_inheritance_children(RelationGetRelid(rel), lockmode);
if (children)
{
Relation attr_rel;
ListCell *child;
attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
Relation childrel;
Form_pg_attribute childatt;
/* find_inheritance_children already got lock */
childrel = heap_open(childrelid, NoLock); CheckTableNotInUse(childrel, "ALTER TABLE");
tuple = SearchSysCacheCopyAttName(childrelid, colName);
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for attribute \"%s\" of relation %u",
colName, childrelid);
childatt = (Form_pg_attribute) GETSTRUCT(tuple);
if (childatt->attinhcount <= 0) /* shouldn't happen */
elog(ERROR, "relation %u has non-inherited attribute \"%s\"",
childrelid, colName);
if (recurse)
{
/*
* If the child column has other definition sources, just
* decrement its inheritance count; if not, recurse to delete
* it.
*/
if (childatt->attinhcount == 1 && !childatt->attislocal)
{
/* Time to delete this child column, too */
ATExecDropColumn(wqueue, childrel, colName,
behavior, true, true,
false, lockmode);
}
else
{
/* Child column must survive my deletion */
childatt->attinhcount--;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
/* Make update visible */
CommandCounterIncrement();
}
}
else
{
/*
* If we were told to drop ONLY in this table (no recursion),
* we need to mark the inheritors' attributes as locally
* defined rather than inherited.
*/
childatt->attinhcount--;
childatt->attislocal = true;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
/* Make update visible */
CommandCounterIncrement();
}
heap_freetuple(tuple);
heap_close(childrel, NoLock);
}
heap_close(attr_rel, RowExclusiveLock);
}
/*
* Perform the actual column deletion
*/
object.classId = RelationRelationId; object.objectId = RelationGetRelid(rel);
object.objectSubId = attnum;
performDeletion(&object, behavior);
/*
* If we dropped the OID column, must adjust pg_class.relhasoids and tell
* Phase 3 to physically get rid of the column.
*/
if (attnum == ObjectIdAttributeNumber)
{
Relation class_rel;
Form_pg_class tuple_class;
AlteredTableInfo *tab;
class_rel = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy1(RELOID,
ObjectIdGetDatum(RelationGetRelid(rel)));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u",
RelationGetRelid(rel));
tuple_class = (Form_pg_class) GETSTRUCT(tuple);
tuple_class->relhasoids = false;
simple_heap_update(class_rel, &tuple->t_self, tuple);
/* Keep the catalog indexes up to date */
CatalogUpdateIndexes(class_rel, tuple);
heap_close(class_rel, RowExclusiveLock);
/* Find or create work queue entry for this table */
tab = ATGetQueueEntry(wqueue, rel);
/* Tell Phase 3 to physically remove the OID column */
tab->new_changeoids = true;
}
}
/*
* ALTER TABLE ADD INDEX
*
* There is no such command in the grammar, but parse_utilcmd.c converts
* UNIQUE and PRIMARY KEY constraints into AT_AddIndex subcommands. This lets
* us schedule creation of the index at the appropriate time during ALTER.
*/
static void
ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
IndexStmt *stmt, bool is_rebuild, LOCKMODE lockmode)
{
bool check_rights;
bool skip_build;
bool quiet;
Assert(IsA(stmt, IndexStmt));
/* suppress schema rights check when rebuilding existing index */
check_rights = !is_rebuild;
/* skip index build if phase 3 will have to rewrite table anyway */
skip_build = (tab->newvals != NIL);
/* suppress notices when rebuilding existing index */
quiet = is_rebuild;
/* The IndexStmt has already been through transformIndexStmt */
DefineIndex(stmt->relation, /* relation */
stmt->idxname, /* index name */
InvalidOid, /* no predefined OID */
stmt->accessMethod, /* am name */ stmt->tableSpace,
stmt->indexParams, /* parameters */
(Expr *) stmt->whereClause,
stmt->options,
stmt->excludeOpNames,
stmt->unique,
stmt->primary,
stmt->isconstraint,
stmt->deferrable,
stmt->initdeferred,
true, /* is_alter_table */
check_rights,
skip_build,
quiet,
false);
}
/*
* ALTER TABLE ADD CONSTRAINT
*/
static void
ATExecAddConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
Constraint *newConstraint, bool recurse, LOCKMODE lockmode)
{
Assert(IsA(newConstraint, Constraint));
/*
* Currently, we only expect to see CONSTR_CHECK and CONSTR_FOREIGN nodes
* arriving here (see the preprocessing done in parse_utilcmd.c). Use a
* switch anyway to make it easier to add more code later.
*/
switch (newConstraint->contype)
{
case CONSTR_CHECK:
ATAddCheckConstraint(wqueue, tab, rel,
newConstraint, recurse, false, lockmode);
break;
case CONSTR_FOREIGN:
/*
* Note that we currently never recurse for FK constraints, so the
* "recurse" flag is silently ignored.
*
* Assign or validate constraint name
*/
if (newConstraint->conname)
{
if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
RelationGetRelid(rel),
RelationGetNamespace(rel),
newConstraint->conname))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("constraint \"%s\" for relation \"%s\" already exists",
newConstraint->conname,
RelationGetRelationName(rel))));
}
else
newConstraint->conname =
ChooseConstraintName(RelationGetRelationName(rel),
strVal(linitial(newConstraint->fk_attrs)),
"fkey",
RelationGetNamespace(rel),
NIL);
ATAddForeignKeyConstraint(tab, rel, newConstraint, lockmode);
break;
default: elog(ERROR, "unrecognized constraint type: %d",
(int) newConstraint->contype);
}
}
/*
* Add a check constraint to a single table and its children
*
* Subroutine for ATExecAddConstraint.
*
* We must recurse to child tables during execution, rather than using
* ALTER TABLE's normal prep-time recursion. The reason is that all the
* constraints *must* be given the same name, else they won't be seen as
* related later. If the user didn't explicitly specify a name, then
* AddRelationNewConstraints would normally assign different names to the
* child constraints. To fix that, we must capture the name assigned at
* the parent table and pass that down.
*/
static void
ATAddCheckConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
Constraint *constr, bool recurse, bool recursing,
LOCKMODE lockmode)
{
List *newcons;
ListCell *lcon;
List *children;
ListCell *child;
/* At top level, permission check was done in ATPrepCmd, else do it */
if (recursing)
ATSimplePermissions(rel, false);
/*
* Call AddRelationNewConstraints to do the work, making sure it works on
* a copy of the Constraint so transformExpr can't modify the original. It
* returns a list of cooked constraints.
*
* If the constraint ends up getting merged with a pre-existing one, it's
* omitted from the returned list, which is what we want: we do not need
* to do any validation work. That can only happen at child tables,
* though, since we disallow merging at the top level.
*/
newcons = AddRelationNewConstraints(rel, NIL,
list_make1(copyObject(constr)),
recursing, !recursing);
/* Add each constraint to Phase 3's queue */
foreach(lcon, newcons)
{
CookedConstraint *ccon = (CookedConstraint *) lfirst(lcon);
NewConstraint *newcon;
newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
newcon->name = ccon->name;
newcon->contype = ccon->contype;
/* ExecQual wants implicit-AND format */
newcon->qual = (Node *) make_ands_implicit((Expr *) ccon->expr);
tab->constraints = lappend(tab->constraints, newcon);
/* Save the actually assigned name if it was defaulted */
if (constr->conname == NULL)
constr->conname = ccon->name;
}
/* At this point we must have a locked-down name to use */
Assert(constr->conname != NULL);
/* Advance command counter in case same table is visited multiple times */
CommandCounterIncrement();
/*
* If the constraint got merged with an existing constraint, we're done.
* We mustn't recurse to child tables in this case, because they've already
* got the constraint, and visiting them again would lead to an incorrect
* value for coninhcount.
*/
if (newcons == NIL)
return;
/*
* Propagate to children as appropriate. Unlike most other ALTER
* routines, we have to do this one level of recursion at a time; we can't
* use find_all_inheritors to do it in one pass.
*/
children = find_inheritance_children(RelationGetRelid(rel), lockmode);
/*
* If we are told not to recurse, there had better not be any child
* tables; else the addition would put them out of step.
*/
if (children && !recurse)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("constraint must be added to child tables too")));
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
Relation childrel;
AlteredTableInfo *childtab;
/* find_inheritance_children already got lock */
childrel = heap_open(childrelid, NoLock);
CheckTableNotInUse(childrel, "ALTER TABLE");
/* Find or create work queue entry for this table */
childtab = ATGetQueueEntry(wqueue, childrel);
/* Recurse to child */
ATAddCheckConstraint(wqueue, childtab, childrel,
constr, recurse, true, lockmode);
heap_close(childrel, NoLock);
}
}
/*
* Add a foreign-key constraint to a single table
*
* Subroutine for ATExecAddConstraint. Must already hold exclusive
* lock on the rel, and have done appropriate validity checks for it.
* We do permissions checks here, however.
*/
static void
ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
Constraint *fkconstraint, LOCKMODE lockmode)
{
Relation pkrel;
int16 pkattnum[INDEX_MAX_KEYS];
int16 fkattnum[INDEX_MAX_KEYS];
Oid pktypoid[INDEX_MAX_KEYS];
Oid fktypoid[INDEX_MAX_KEYS];
Oid opclasses[INDEX_MAX_KEYS];
Oid pfeqoperators[INDEX_MAX_KEYS];
Oid ppeqoperators[INDEX_MAX_KEYS];
Oid ffeqoperators[INDEX_MAX_KEYS];
int i;
int numfks,
numpks; Oid indexOid;
Oid constrOid;
pkrel = heap_openrv(fkconstraint->pktable, lockmode);
/*
* Validity checks (permission checks wait till we have the column
* numbers)
*/
if (pkrel->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("referenced relation \"%s\" is not a table",
RelationGetRelationName(pkrel))));
if (!allowSystemTableMods && IsSystemRelation(pkrel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(pkrel))));
/*
* Disallow reference from permanent table to temp table or vice versa.
* (The ban on perm->temp is for fairly obvious reasons. The ban on
* temp->perm is because other backends might need to run the RI triggers
* on the perm table, but they can't reliably see tuples the owning
* backend has created in the temp table, because non-shared buffers are
* used for temp tables.)
*/
if (pkrel->rd_istemp)
{
if (!rel->rd_istemp)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot reference temporary table from permanent table constraint")));
}
else
{
if (rel->rd_istemp)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot reference permanent table from temporary table constraint")));
}
/*
* Look up the referencing attributes to make sure they exist, and record
* their attnums and type OIDs.
*/
MemSet(pkattnum, 0, sizeof(pkattnum));
MemSet(fkattnum, 0, sizeof(fkattnum));
MemSet(pktypoid, 0, sizeof(pktypoid));
MemSet(fktypoid, 0, sizeof(fktypoid));
MemSet(opclasses, 0, sizeof(opclasses));
MemSet(pfeqoperators, 0, sizeof(pfeqoperators));
MemSet(ppeqoperators, 0, sizeof(ppeqoperators));
MemSet(ffeqoperators, 0, sizeof(ffeqoperators));
numfks = transformColumnNameList(RelationGetRelid(rel),
fkconstraint->fk_attrs,
fkattnum, fktypoid);
/*
* If the attribute list for the referenced table was omitted, lookup the
* definition of the primary key and use it. Otherwise, validate the
* supplied attribute list. In either case, discover the index OID and
* index opclasses, and the attnums and type OIDs of the attributes.
*/
if (fkconstraint->pk_attrs == NIL)
{
numpks = transformFkeyGetPrimaryKey(pkrel, &indexOid, &fkconstraint->pk_attrs,
pkattnum, pktypoid,
opclasses);
}
else
{
numpks = transformColumnNameList(RelationGetRelid(pkrel),
fkconstraint->pk_attrs,
pkattnum, pktypoid);
/* Look for an index matching the column list */
indexOid = transformFkeyCheckAttrs(pkrel, numpks, pkattnum,
opclasses);
}
/*
* Now we can check permissions.
*/
checkFkeyPermissions(pkrel, pkattnum, numpks);
checkFkeyPermissions(rel, fkattnum, numfks);
/*
* Look up the equality operators to use in the constraint.
*
* Note that we have to be careful about the difference between the actual
* PK column type and the opclass' declared input type, which might be
* only binary-compatible with it. The declared opcintype is the right
* thing to probe pg_amop with.
*/
if (numfks != numpks)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FOREIGN_KEY),
errmsg("number of referencing and referenced columns for foreign key disagree")));
for (i = 0; i < numpks; i++)
{
Oid pktype = pktypoid[i];
Oid fktype = fktypoid[i];
Oid fktyped;
HeapTuple cla_ht;
Form_pg_opclass cla_tup;
Oid amid;
Oid opfamily;
Oid opcintype;
Oid pfeqop;
Oid ppeqop;
Oid ffeqop;
int16 eqstrategy;
/* We need several fields out of the pg_opclass entry */
cla_ht = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclasses[i]));
if (!HeapTupleIsValid(cla_ht))
elog(ERROR, "cache lookup failed for opclass %u", opclasses[i]);
cla_tup = (Form_pg_opclass) GETSTRUCT(cla_ht);
amid = cla_tup->opcmethod;
opfamily = cla_tup->opcfamily;
opcintype = cla_tup->opcintype;
ReleaseSysCache(cla_ht);
/*
* Check it's a btree; currently this can never fail since no other
* index AMs support unique indexes. If we ever did have other types
* of unique indexes, we'd need a way to determine which operator
* strategy number is equality. (Is it reasonable to insist that
* every such index AM use btree's number for equality?)
*/
if (amid != BTREE_AM_OID)
elog(ERROR, "only b-tree indexes are supported for foreign keys");
eqstrategy = BTEqualStrategyNumber;
/* * There had better be a primary equality operator for the index.
* We'll use it for PK = PK comparisons.
*/
ppeqop = get_opfamily_member(opfamily, opcintype, opcintype,
eqstrategy);
if (!OidIsValid(ppeqop))
elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
eqstrategy, opcintype, opcintype, opfamily);
/*
* Are there equality operators that take exactly the FK type? Assume
* we should look through any domain here.
*/
fktyped = getBaseType(fktype);
pfeqop = get_opfamily_member(opfamily, opcintype, fktyped,
eqstrategy);
if (OidIsValid(pfeqop))
ffeqop = get_opfamily_member(opfamily, fktyped, fktyped,
eqstrategy);
else
ffeqop = InvalidOid; /* keep compiler quiet */
if (!(OidIsValid(pfeqop) && OidIsValid(ffeqop)))
{
/*
* Otherwise, look for an implicit cast from the FK type to the
* opcintype, and if found, use the primary equality operator.
* This is a bit tricky because opcintype might be a polymorphic
* type such as ANYARRAY or ANYENUM; so what we have to test is
* whether the two actual column types can be concurrently cast to
* that type. (Otherwise, we'd fail to reject combinations such
* as int[] and point[].)
*/
Oid input_typeids[2];
Oid target_typeids[2];
input_typeids[0] = pktype;
input_typeids[1] = fktype;
target_typeids[0] = opcintype;
target_typeids[1] = opcintype;
if (can_coerce_type(2, input_typeids, target_typeids,
COERCION_IMPLICIT))
pfeqop = ffeqop = ppeqop;
}
if (!(OidIsValid(pfeqop) && OidIsValid(ffeqop)))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("foreign key constraint \"%s\" "
"cannot be implemented",
fkconstraint->conname),
errdetail("Key columns \"%s\" and \"%s\" "
"are of incompatible types: %s and %s.",
strVal(list_nth(fkconstraint->fk_attrs, i)),
strVal(list_nth(fkconstraint->pk_attrs, i)),
format_type_be(fktype),
format_type_be(pktype))));
pfeqoperators[i] = pfeqop;
ppeqoperators[i] = ppeqop;
ffeqoperators[i] = ffeqop;
}
/*
* Record the FK constraint in pg_constraint.
*/
constrOid = CreateConstraintEntry(fkconstraint->conname,
RelationGetNamespace(rel), CONSTRAINT_FOREIGN,
fkconstraint->deferrable,
fkconstraint->initdeferred,
RelationGetRelid(rel),
fkattnum,
numfks,
InvalidOid, /* not a domain
* constraint */
indexOid,
RelationGetRelid(pkrel),
pkattnum,
pfeqoperators,
ppeqoperators,
ffeqoperators,
numpks,
fkconstraint->fk_upd_action,
fkconstraint->fk_del_action,
fkconstraint->fk_matchtype,
NULL, /* no exclusion constraint */
NULL, /* no check constraint */
NULL,
NULL,
true, /* islocal */
0); /* inhcount */
/*
* Create the triggers that will enforce the constraint.
*/
createForeignKeyTriggers(rel, fkconstraint, constrOid, indexOid);
/*
* Tell Phase 3 to check that the constraint is satisfied by existing rows
* (we can skip this during table creation).
*/
if (!fkconstraint->skip_validation)
{
NewConstraint *newcon;
newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
newcon->name = fkconstraint->conname;
newcon->contype = CONSTR_FOREIGN;
newcon->refrelid = RelationGetRelid(pkrel);
newcon->refindid = indexOid;
newcon->conid = constrOid;
newcon->qual = (Node *) fkconstraint;
tab->constraints = lappend(tab->constraints, newcon);
}
/*
* Close pk table, but keep lock until we've committed.
*/
heap_close(pkrel, NoLock);
}
/*
* transformColumnNameList - transform list of column names
*
* Lookup each name and return its attnum and type OID
*/
static int
transformColumnNameList(Oid relId, List *colList,
int16 *attnums, Oid *atttypids)
{
ListCell *l;
int attnum;
attnum = 0;
foreach(l, colList) {
char *attname = strVal(lfirst(l));
HeapTuple atttuple;
atttuple = SearchSysCacheAttName(relId, attname);
if (!HeapTupleIsValid(atttuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" referenced in foreign key constraint does not exist",
attname)));
if (attnum >= INDEX_MAX_KEYS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("cannot have more than %d keys in a foreign key",
INDEX_MAX_KEYS)));
attnums[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->attnum;
atttypids[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->atttypid;
ReleaseSysCache(atttuple);
attnum++;
}
return attnum;
}
/*
* transformFkeyGetPrimaryKey -
*
* Look up the names, attnums, and types of the primary key attributes
* for the pkrel. Also return the index OID and index opclasses of the
* index supporting the primary key.
*
* All parameters except pkrel are output parameters. Also, the function
* return value is the number of attributes in the primary key.
*
* Used when the column list in the REFERENCES specification is omitted.
*/
static int
transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
List **attnamelist,
int16 *attnums, Oid *atttypids,
Oid *opclasses)
{
List *indexoidlist;
ListCell *indexoidscan;
HeapTuple indexTuple = NULL;
Form_pg_index indexStruct = NULL;
Datum indclassDatum;
bool isnull;
oidvector *indclass;
int i;
/*
* Get the list of index OIDs for the table from the relcache, and look up
* each one in the pg_index syscache until we find one marked primary key
* (hopefully there isn't more than one such).
*/
*indexOid = InvalidOid;
indexoidlist = RelationGetIndexList(pkrel);
foreach(indexoidscan, indexoidlist)
{
Oid indexoid = lfirst_oid(indexoidscan);
indexTuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexoid));
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexoid);
indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
if (indexStruct->indisprimary)
{ /*
* Refuse to use a deferrable primary key. This is per SQL spec,
* and there would be a lot of interesting semantic problems if we
* tried to allow it.
*/
if (!indexStruct->indimmediate)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot use a deferrable primary key for referenced table \"%s\"",
RelationGetRelationName(pkrel))));
*indexOid = indexoid;
break;
}
ReleaseSysCache(indexTuple);
}
list_free(indexoidlist);
/*
* Check that we found it
*/
if (!OidIsValid(*indexOid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("there is no primary key for referenced table \"%s\"",
RelationGetRelationName(pkrel))));
/* Must get indclass the hard way */
indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
Anum_pg_index_indclass, &isnull);
Assert(!isnull);
indclass = (oidvector *) DatumGetPointer(indclassDatum);
/*
* Now build the list of PK attributes from the indkey definition (we
* assume a primary key cannot have expressional elements)
*/
*attnamelist = NIL;
for (i = 0; i < indexStruct->indnatts; i++)
{
int pkattno = indexStruct->indkey.values[i];
attnums[i] = pkattno;
atttypids[i] = attnumTypeId(pkrel, pkattno);
opclasses[i] = indclass->values[i];
*attnamelist = lappend(*attnamelist,
makeString(pstrdup(NameStr(*attnumAttName(pkrel, pkattno)))));
}
ReleaseSysCache(indexTuple);
return i;
}
/*
* transformFkeyCheckAttrs -
*
* Make sure that the attributes of a referenced table belong to a unique
* (or primary key) constraint. Return the OID of the index supporting
* the constraint, as well as the opclasses associated with the index
* columns.
*/
static Oid
transformFkeyCheckAttrs(Relation pkrel,
int numattrs, int16 *attnums,
Oid *opclasses) /* output parameter */
{
Oid indexoid = InvalidOid;
bool found = false; bool found_deferrable = false;
List *indexoidlist;
ListCell *indexoidscan;
/*
* Get the list of index OIDs for the table from the relcache, and look up
* each one in the pg_index syscache, and match unique indexes to the list
* of attnums we are given.
*/
indexoidlist = RelationGetIndexList(pkrel);
foreach(indexoidscan, indexoidlist)
{
HeapTuple indexTuple;
Form_pg_index indexStruct;
int i,
j;
indexoid = lfirst_oid(indexoidscan);
indexTuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexoid));
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexoid);
indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
/*
* Must have the right number of columns; must be unique and not a
* partial index; forget it if there are any expressions, too
*/
if (indexStruct->indnatts == numattrs &&
indexStruct->indisunique &&
heap_attisnull(indexTuple, Anum_pg_index_indpred) &&
heap_attisnull(indexTuple, Anum_pg_index_indexprs))
{
/* Must get indclass the hard way */
Datum indclassDatum;
bool isnull;
oidvector *indclass;
indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
Anum_pg_index_indclass, &isnull);
Assert(!isnull);
indclass = (oidvector *) DatumGetPointer(indclassDatum);
/*
* The given attnum list may match the index columns in any order.
* Check that each list is a subset of the other.
*/
for (i = 0; i < numattrs; i++)
{
found = false;
for (j = 0; j < numattrs; j++)
{
if (attnums[i] == indexStruct->indkey.values[j])
{
found = true;
break;
}
}
if (!found)
break;
}
if (found)
{
for (i = 0; i < numattrs; i++)
{
found = false;
for (j = 0; j < numattrs; j++)
{
if (attnums[j] == indexStruct->indkey.values[i])
{ opclasses[j] = indclass->values[i];
found = true;
break;
}
}
if (!found)
break;
}
}
/*
* Refuse to use a deferrable unique/primary key. This is per SQL
* spec, and there would be a lot of interesting semantic problems
* if we tried to allow it.
*/
if (found && !indexStruct->indimmediate)
{
/*
* Remember that we found an otherwise matching index, so that
* we can generate a more appropriate error message.
*/
found_deferrable = true;
found = false;
}
}
ReleaseSysCache(indexTuple);
if (found)
break;
}
if (!found)
{
if (found_deferrable)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot use a deferrable unique constraint for referenced table \"%s\"",
RelationGetRelationName(pkrel))));
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_FOREIGN_KEY),
errmsg("there is no unique constraint matching given keys for referenced table \"%s\"",
RelationGetRelationName(pkrel))));
}
list_free(indexoidlist);
return indexoid;
}
/* Permissions checks for ADD FOREIGN KEY */
static void
checkFkeyPermissions(Relation rel, int16 *attnums, int natts)
{
Oid roleid = GetUserId();
AclResult aclresult;
int i;
/* Okay if we have relation-level REFERENCES permission */
aclresult = pg_class_aclcheck(RelationGetRelid(rel), roleid,
ACL_REFERENCES);
if (aclresult == ACLCHECK_OK)
return;
/* Else we must have REFERENCES on each column */
for (i = 0; i < natts; i++)
{
aclresult = pg_attribute_aclcheck(RelationGetRelid(rel), attnums[i],
roleid, ACL_REFERENCES);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(rel)); }
}
/*
* Scan the existing rows in a table to verify they meet a proposed FK
* constraint.
*
* Caller must have opened and locked both relations appropriately.
*/
static void
validateForeignKeyConstraint(Constraint *fkconstraint,
Relation rel,
Relation pkrel,
Oid pkindOid,
Oid constraintOid)
{
HeapScanDesc scan;
HeapTuple tuple;
Trigger trig;
/*
* Build a trigger call structure; we'll need it either way.
*/
MemSet(&trig, 0, sizeof(trig));
trig.tgoid = InvalidOid;
trig.tgname = fkconstraint->conname;
trig.tgenabled = TRIGGER_FIRES_ON_ORIGIN;
trig.tgisinternal = TRUE;
trig.tgconstrrelid = RelationGetRelid(pkrel);
trig.tgconstrindid = pkindOid;
trig.tgconstraint = constraintOid;
trig.tgdeferrable = FALSE;
trig.tginitdeferred = FALSE;
/* we needn't fill in tgargs or tgqual */
/*
* See if we can do it with a single LEFT JOIN query. A FALSE result
* indicates we must proceed with the fire-the-trigger method.
*/
if (RI_Initial_Check(&trig, rel, pkrel))
return;
/*
* Scan through each tuple, calling RI_FKey_check_ins (insert trigger) as
* if that tuple had just been inserted. If any of those fail, it should
* ereport(ERROR) and that's that.
*/
scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
FunctionCallInfoData fcinfo;
TriggerData trigdata;
/*
* Make a call to the trigger function
*
* No parameters are passed, but we do set a context
*/
MemSet(&fcinfo, 0, sizeof(fcinfo));
/*
* We assume RI_FKey_check_ins won't look at flinfo...
*/
trigdata.type = T_TriggerData;
trigdata.tg_event = TRIGGER_EVENT_INSERT | TRIGGER_EVENT_ROW;
trigdata.tg_relation = rel;
trigdata.tg_trigtuple = tuple;
trigdata.tg_newtuple = NULL;
trigdata.tg_trigger = &trig; trigdata.tg_trigtuplebuf = scan->rs_cbuf;
trigdata.tg_newtuplebuf = InvalidBuffer;
fcinfo.context = (Node *) &trigdata;
RI_FKey_check_ins(&fcinfo);
}
heap_endscan(scan);
}
static void
CreateFKCheckTrigger(RangeVar *myRel, Constraint *fkconstraint,
Oid constraintOid, Oid indexOid, bool on_insert)
{
CreateTrigStmt *fk_trigger;
fk_trigger = makeNode(CreateTrigStmt);
fk_trigger->trigname = "RI_ConstraintTrigger";
fk_trigger->relation = myRel;
fk_trigger->before = false;
fk_trigger->row = true;
/* Either ON INSERT or ON UPDATE */
if (on_insert)
{
fk_trigger->funcname = SystemFuncName("RI_FKey_check_ins");
fk_trigger->events = TRIGGER_TYPE_INSERT;
}
else
{
fk_trigger->funcname = SystemFuncName("RI_FKey_check_upd");
fk_trigger->events = TRIGGER_TYPE_UPDATE;
}
fk_trigger->columns = NIL;
fk_trigger->whenClause = NULL;
fk_trigger->isconstraint = true;
fk_trigger->deferrable = fkconstraint->deferrable;
fk_trigger->initdeferred = fkconstraint->initdeferred;
fk_trigger->constrrel = fkconstraint->pktable;
fk_trigger->args = NIL;
(void) CreateTrigger(fk_trigger, NULL, constraintOid, indexOid, true);
/* Make changes-so-far visible */
CommandCounterIncrement();
}
/*
* Create the triggers that implement an FK constraint.
*/
static void
createForeignKeyTriggers(Relation rel, Constraint *fkconstraint,
Oid constraintOid, Oid indexOid)
{
RangeVar *myRel;
CreateTrigStmt *fk_trigger;
/*
* Reconstruct a RangeVar for my relation (not passed in, unfortunately).
*/
myRel = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)),
pstrdup(RelationGetRelationName(rel)),
-1);
/* Make changes-so-far visible */
CommandCounterIncrement();
/* * Build and execute a CREATE CONSTRAINT TRIGGER statement for the CHECK
* action for both INSERTs and UPDATEs on the referencing table.
*/
CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, indexOid, true);
CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, indexOid, false);
/*
* Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
* DELETE action on the referenced table.
*/
fk_trigger = makeNode(CreateTrigStmt);
fk_trigger->trigname = "RI_ConstraintTrigger";
fk_trigger->relation = fkconstraint->pktable;
fk_trigger->before = false;
fk_trigger->row = true;
fk_trigger->events = TRIGGER_TYPE_DELETE;
fk_trigger->columns = NIL;
fk_trigger->whenClause = NULL;
fk_trigger->isconstraint = true;
fk_trigger->constrrel = myRel;
switch (fkconstraint->fk_del_action)
{
case FKCONSTR_ACTION_NOACTION:
fk_trigger->deferrable = fkconstraint->deferrable;
fk_trigger->initdeferred = fkconstraint->initdeferred;
fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_del");
break;
case FKCONSTR_ACTION_RESTRICT:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_del");
break;
case FKCONSTR_ACTION_CASCADE:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_del");
break;
case FKCONSTR_ACTION_SETNULL:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_del");
break;
case FKCONSTR_ACTION_SETDEFAULT:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_del");
break;
default:
elog(ERROR, "unrecognized FK action type: %d",
(int) fkconstraint->fk_del_action);
break;
}
fk_trigger->args = NIL;
(void) CreateTrigger(fk_trigger, NULL, constraintOid, indexOid, true);
/* Make changes-so-far visible */
CommandCounterIncrement();
/*
* Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
* UPDATE action on the referenced table.
*/
fk_trigger = makeNode(CreateTrigStmt);
fk_trigger->trigname = "RI_ConstraintTrigger";
fk_trigger->relation = fkconstraint->pktable;
fk_trigger->before = false;
fk_trigger->row = true;
fk_trigger->events = TRIGGER_TYPE_UPDATE;
fk_trigger->columns = NIL; fk_trigger->whenClause = NULL;
fk_trigger->isconstraint = true;
fk_trigger->constrrel = myRel;
switch (fkconstraint->fk_upd_action)
{
case FKCONSTR_ACTION_NOACTION:
fk_trigger->deferrable = fkconstraint->deferrable;
fk_trigger->initdeferred = fkconstraint->initdeferred;
fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_upd");
break;
case FKCONSTR_ACTION_RESTRICT:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_upd");
break;
case FKCONSTR_ACTION_CASCADE:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_upd");
break;
case FKCONSTR_ACTION_SETNULL:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_upd");
break;
case FKCONSTR_ACTION_SETDEFAULT:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_upd");
break;
default:
elog(ERROR, "unrecognized FK action type: %d",
(int) fkconstraint->fk_upd_action);
break;
}
fk_trigger->args = NIL;
(void) CreateTrigger(fk_trigger, NULL, constraintOid, indexOid, true);
}
/*
* ALTER TABLE DROP CONSTRAINT
*
* Like DROP COLUMN, we can't use the normal ALTER TABLE recursion mechanism.
*/
static void
ATExecDropConstraint(Relation rel, const char *constrName,
DropBehavior behavior,
bool recurse, bool recursing,
bool missing_ok, LOCKMODE lockmode)
{
List *children;
ListCell *child;
Relation conrel;
Form_pg_constraint con;
SysScanDesc scan;
ScanKeyData key;
HeapTuple tuple;
bool found = false;
bool is_check_constraint = false;
/* At top level, permission check was done in ATPrepCmd, else do it */
if (recursing)
ATSimplePermissions(rel, false);
conrel = heap_open(ConstraintRelationId, RowExclusiveLock);
/*
* Find and drop the target constraint
*/ ScanKeyInit(&key,
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
scan = systable_beginscan(conrel, ConstraintRelidIndexId,
true, SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
{
ObjectAddress conobj;
con = (Form_pg_constraint) GETSTRUCT(tuple);
if (strcmp(NameStr(con->conname), constrName) != 0)
continue;
/* Don't drop inherited constraints */
if (con->coninhcount > 0 && !recursing)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot drop inherited constraint \"%s\" of relation \"%s\"",
constrName, RelationGetRelationName(rel))));
/* Right now only CHECK constraints can be inherited */
if (con->contype == CONSTRAINT_CHECK)
is_check_constraint = true;
/*
* Perform the actual constraint deletion
*/
conobj.classId = ConstraintRelationId;
conobj.objectId = HeapTupleGetOid(tuple);
conobj.objectSubId = 0;
performDeletion(&conobj, behavior);
found = true;
}
systable_endscan(scan);
if (!found)
{
if (!missing_ok)
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("constraint \"%s\" of relation \"%s\" does not exist",
constrName, RelationGetRelationName(rel))));
}
else
{
ereport(NOTICE,
(errmsg("constraint \"%s\" of relation \"%s\" does not exist, skipping",
constrName, RelationGetRelationName(rel))));
heap_close(conrel, RowExclusiveLock);
return;
}
}
/*
* Propagate to children as appropriate. Unlike most other ALTER
* routines, we have to do this one level of recursion at a time; we can't
* use find_all_inheritors to do it in one pass.
*/
if (is_check_constraint)
children = find_inheritance_children(RelationGetRelid(rel), lockmode);
else
children = NIL;
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
Relation childrel;
/* find_inheritance_children already got lock */
childrel = heap_open(childrelid, NoLock);
CheckTableNotInUse(childrel, "ALTER TABLE");
ScanKeyInit(&key,
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(childrelid));
scan = systable_beginscan(conrel, ConstraintRelidIndexId,
true, SnapshotNow, 1, &key);
found = false;
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
{
HeapTuple copy_tuple;
con = (Form_pg_constraint) GETSTRUCT(tuple);
/* Right now only CHECK constraints can be inherited */
if (con->contype != CONSTRAINT_CHECK)
continue;
if (strcmp(NameStr(con->conname), constrName) != 0)
continue;
found = true;
if (con->coninhcount <= 0) /* shouldn't happen */
elog(ERROR, "relation %u has non-inherited constraint \"%s\"",
childrelid, constrName);
copy_tuple = heap_copytuple(tuple);
con = (Form_pg_constraint) GETSTRUCT(copy_tuple);
if (recurse)
{
/*
* If the child constraint has other definition sources, just
* decrement its inheritance count; if not, recurse to delete
* it.
*/
if (con->coninhcount == 1 && !con->conislocal)
{
/* Time to delete this child constraint, too */
ATExecDropConstraint(childrel, constrName, behavior,
true, true,
false, lockmode);
}
else
{
/* Child constraint must survive my deletion */
con->coninhcount--;
simple_heap_update(conrel, ©_tuple->t_self, copy_tuple);
CatalogUpdateIndexes(conrel, copy_tuple);
/* Make update visible */
CommandCounterIncrement();
}
}
else
{
/*
* If we were told to drop ONLY in this table (no recursion),
* we need to mark the inheritors' constraints as locally * defined rather than inherited.
*/
con->coninhcount--;
con->conislocal = true;
simple_heap_update(conrel, ©_tuple->t_self, copy_tuple);
CatalogUpdateIndexes(conrel, copy_tuple);
/* Make update visible */
CommandCounterIncrement();
}
heap_freetuple(copy_tuple);
}
systable_endscan(scan);
if (!found)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("constraint \"%s\" of relation \"%s\" does not exist",
constrName,
RelationGetRelationName(childrel))));
heap_close(childrel, NoLock);
}
heap_close(conrel, RowExclusiveLock);
}
/*
* ALTER COLUMN TYPE
*/
static void
ATPrepAlterColumnType(List **wqueue,
AlteredTableInfo *tab, Relation rel,
bool recurse, bool recursing,
AlterTableCmd *cmd, LOCKMODE lockmode)
{
char *colName = cmd->name;
TypeName *typeName = (TypeName *) cmd->def;
HeapTuple tuple;
Form_pg_attribute attTup;
AttrNumber attnum;
Oid targettype;
int32 targettypmod;
Node *transform;
NewColumnValue *newval;
ParseState *pstate = make_parsestate(NULL);
if (rel->rd_rel->reloftype)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot alter column type of typed table")));
/* lookup the attribute so we can check inheritance status */
tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attTup = (Form_pg_attribute) GETSTRUCT(tuple);
attnum = attTup->attnum;
/* Can't alter a system attribute */
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"", colName)));
/* Don't alter inherited columns */
if (attTup->attinhcount > 0 && !recursing)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot alter inherited column \"%s\"",
colName)));
/* Look up the target type */
targettype = typenameTypeId(NULL, typeName, &targettypmod);
/* make sure datatype is legal for a column */
CheckAttributeType(colName, targettype, false);
/*
* Set up an expression to transform the old data value to the new type.
* If a USING option was given, transform and use that expression, else
* just take the old value and try to coerce it. We do this first so that
* type incompatibility can be detected before we waste effort, and
* because we need the expression to be parsed against the original table
* rowtype.
*/
if (cmd->transform)
{
RangeTblEntry *rte;
/* Expression must be able to access vars of old table */
rte = addRangeTableEntryForRelation(pstate,
rel,
NULL,
false,
true);
addRTEtoQuery(pstate, rte, false, true, true);
transform = transformExpr(pstate, cmd->transform);
/* It can't return a set */
if (expression_returns_set(transform))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("transform expression must not return a set")));
/* No subplans or aggregates, either... */
if (pstate->p_hasSubLinks)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot use subquery in transform expression")));
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in transform expression")));
if (pstate->p_hasWindowFuncs)
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("cannot use window function in transform expression")));
}
else
{
transform = (Node *) makeVar(1, attnum,
attTup->atttypid, attTup->atttypmod,
0);
}
transform = coerce_to_target_type(pstate,
transform, exprType(transform),
targettype, targettypmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST,
-1); if (transform == NULL)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" cannot be cast to type %s",
colName, format_type_be(targettype))));
/*
* Add a work queue item to make ATRewriteTable update the column
* contents.
*/
newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
newval->attnum = attnum;
newval->expr = (Expr *) transform;
tab->newvals = lappend(tab->newvals, newval);
ReleaseSysCache(tuple);
/*
* The recursion case is handled by ATSimpleRecursion. However, if we are
* told not to recurse, there had better not be any child tables; else the
* alter would put them out of step.
*/
if (recurse)
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
else if (!recursing &&
find_inheritance_children(RelationGetRelid(rel), NoLock) != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("type of inherited column \"%s\" must be changed in child tables too",
colName)));
}
static void
ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
const char *colName, TypeName *typeName, LOCKMODE lockmode)
{
HeapTuple heapTup;
Form_pg_attribute attTup;
AttrNumber attnum;
HeapTuple typeTuple;
Form_pg_type tform;
Oid targettype;
int32 targettypmod;
Node *defaultexpr;
Relation attrelation;
Relation depRel;
ScanKeyData key[3];
SysScanDesc scan;
HeapTuple depTup;
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
/* Look up the target column */
heapTup = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(heapTup)) /* shouldn't happen */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attTup = (Form_pg_attribute) GETSTRUCT(heapTup);
attnum = attTup->attnum;
/* Check for multiple ALTER TYPE on same column --- can't cope */
if (attTup->atttypid != tab->oldDesc->attrs[attnum - 1]->atttypid ||
attTup->atttypmod != tab->oldDesc->attrs[attnum - 1]->atttypmod)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of column \"%s\" twice",
colName)));
/* Look up the target type (should not fail, since prep found it) */
typeTuple = typenameType(NULL, typeName, &targettypmod);
tform = (Form_pg_type) GETSTRUCT(typeTuple);
targettype = HeapTupleGetOid(typeTuple);
/*
* If there is a default expression for the column, get it and ensure we
* can coerce it to the new datatype. (We must do this before changing
* the column type, because build_column_default itself will try to
* coerce, and will not issue the error message we want if it fails.)
*
* We remove any implicit coercion steps at the top level of the old
* default expression; this has been agreed to satisfy the principle of
* least surprise. (The conversion to the new column type should act like
* it started from what the user sees as the stored expression, and the
* implicit coercions aren't going to be shown.)
*/
if (attTup->atthasdef)
{
defaultexpr = build_column_default(rel, attnum);
Assert(defaultexpr);
defaultexpr = strip_implicit_coercions(defaultexpr);
defaultexpr = coerce_to_target_type(NULL, /* no UNKNOWN params */
defaultexpr, exprType(defaultexpr),
targettype, targettypmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST,
-1);
if (defaultexpr == NULL)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("default for column \"%s\" cannot be cast to type %s",
colName, format_type_be(targettype))));
}
else
defaultexpr = NULL;
/*
* Find everything that depends on the column (constraints, indexes, etc),
* and record enough information to let us recreate the objects.
*
* The actual recreation does not happen here, but only after we have
* performed all the individual ALTER TYPE operations. We have to save
* the info before executing ALTER TYPE, though, else the deparser will
* get confused.
*
* There could be multiple entries for the same object, so we must check
* to ensure we process each one only once. Note: we assume that an index
* that implements a constraint will not show a direct dependency on the
* column.
*/
depRel = heap_open(DependRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_depend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
ScanKeyInit(&key[2],
Anum_pg_depend_refobjsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum((int32) attnum));
scan = systable_beginscan(depRel, DependReferenceIndexId, true,
SnapshotNow, 3, key);
while (HeapTupleIsValid(depTup = systable_getnext(scan)))
{
Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
ObjectAddress foundObject;
/* We don't expect any PIN dependencies on columns */
if (foundDep->deptype == DEPENDENCY_PIN)
elog(ERROR, "cannot alter type of a pinned column");
foundObject.classId = foundDep->classid;
foundObject.objectId = foundDep->objid;
foundObject.objectSubId = foundDep->objsubid;
switch (getObjectClass(&foundObject))
{
case OCLASS_CLASS:
{
char relKind = get_rel_relkind(foundObject.objectId);
if (relKind == RELKIND_INDEX)
{
Assert(foundObject.objectSubId == 0);
if (!list_member_oid(tab->changedIndexOids, foundObject.objectId))
{
tab->changedIndexOids = lappend_oid(tab->changedIndexOids,
foundObject.objectId);
tab->changedIndexDefs = lappend(tab->changedIndexDefs,
pg_get_indexdef_string(foundObject.objectId));
}
}
else if (relKind == RELKIND_SEQUENCE)
{
/*
* This must be a SERIAL column's sequence. We need
* not do anything to it.
*/
Assert(foundObject.objectSubId == 0);
}
else
{
/* Not expecting any other direct dependencies... */
elog(ERROR, "unexpected object depending on column: %s",
getObjectDescription(&foundObject));
}
break;
}
case OCLASS_CONSTRAINT:
Assert(foundObject.objectSubId == 0);
if (!list_member_oid(tab->changedConstraintOids,
foundObject.objectId))
{
char *defstring = pg_get_constraintdef_string(foundObject.objectId);
/*
* Put NORMAL dependencies at the front of the list and
* AUTO dependencies at the back. This makes sure that
* foreign-key constraints depending on this column will
* be dropped before unique or primary-key constraints of
* the column; which we must have because the FK
* constraints depend on the indexes belonging to the
* unique constraints.
*/
if (foundDep->deptype == DEPENDENCY_NORMAL)
{
tab->changedConstraintOids =
lcons_oid(foundObject.objectId,
tab->changedConstraintOids);
tab->changedConstraintDefs =
lcons(defstring, tab->changedConstraintDefs);
}
else
{
tab->changedConstraintOids =
lappend_oid(tab->changedConstraintOids,
foundObject.objectId);
tab->changedConstraintDefs =
lappend(tab->changedConstraintDefs,
defstring);
}
}
break;
case OCLASS_REWRITE:
/* XXX someday see if we can cope with revising views */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used by a view or rule"),
errdetail("%s depends on column \"%s\"",
getObjectDescription(&foundObject),
colName)));
break;
case OCLASS_DEFAULT:
/*
* Ignore the column's default expression, since we will fix
* it below.
*/
Assert(defaultexpr);
break;
case OCLASS_PROC:
case OCLASS_TYPE:
case OCLASS_CAST:
case OCLASS_CONVERSION:
case OCLASS_LANGUAGE:
case OCLASS_LARGEOBJECT:
case OCLASS_OPERATOR:
case OCLASS_OPCLASS:
case OCLASS_OPFAMILY:
case OCLASS_AMOP:
case OCLASS_AMPROC:
case OCLASS_TRIGGER:
case OCLASS_SCHEMA:
case OCLASS_TSPARSER:
case OCLASS_TSDICT:
case OCLASS_TSTEMPLATE:
case OCLASS_TSCONFIG:
case OCLASS_ROLE:
case OCLASS_DATABASE:
case OCLASS_TBLSPACE:
case OCLASS_FDW:
case OCLASS_FOREIGN_SERVER:
case OCLASS_USER_MAPPING:
case OCLASS_DEFACL:
/*
* We don't expect any of these sorts of objects to depend on
* a column.
*/
elog(ERROR, "unexpected object depending on column: %s",
getObjectDescription(&foundObject));
break;
default:
elog(ERROR, "unrecognized object class: %u",
foundObject.classId);
} }
systable_endscan(scan);
/*
* Now scan for dependencies of this column on other things. The only
* thing we should find is the dependency on the column datatype, which we
* want to remove.
*/
ScanKeyInit(&key[0],
Anum_pg_depend_classid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_objid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
ScanKeyInit(&key[2],
Anum_pg_depend_objsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum((int32) attnum));
scan = systable_beginscan(depRel, DependDependerIndexId, true,
SnapshotNow, 3, key);
while (HeapTupleIsValid(depTup = systable_getnext(scan)))
{
Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
if (foundDep->deptype != DEPENDENCY_NORMAL)
elog(ERROR, "found unexpected dependency type '%c'",
foundDep->deptype);
if (foundDep->refclassid != TypeRelationId ||
foundDep->refobjid != attTup->atttypid)
elog(ERROR, "found unexpected dependency for column");
simple_heap_delete(depRel, &depTup->t_self);
}
systable_endscan(scan);
heap_close(depRel, RowExclusiveLock);
/*
* Here we go --- change the recorded column type. (Note heapTup is a
* copy of the syscache entry, so okay to scribble on.)
*/
attTup->atttypid = targettype;
attTup->atttypmod = targettypmod;
attTup->attndims = list_length(typeName->arrayBounds);
attTup->attlen = tform->typlen;
attTup->attbyval = tform->typbyval;
attTup->attalign = tform->typalign;
attTup->attstorage = tform->typstorage;
ReleaseSysCache(typeTuple);
simple_heap_update(attrelation, &heapTup->t_self, heapTup);
/* keep system catalog indexes current */
CatalogUpdateIndexes(attrelation, heapTup);
heap_close(attrelation, RowExclusiveLock);
/* Install dependency on new datatype */
add_column_datatype_dependency(RelationGetRelid(rel), attnum, targettype);
/*
* Drop any pg_statistic entry for the column, since it's now wrong type
*/ RemoveStatistics(RelationGetRelid(rel), attnum);
/*
* Update the default, if present, by brute force --- remove and re-add
* the default. Probably unsafe to take shortcuts, since the new version
* may well have additional dependencies. (It's okay to do this now,
* rather than after other ALTER TYPE commands, since the default won't
* depend on other column types.)
*/
if (defaultexpr)
{
/* Must make new row visible since it will be updated again */
CommandCounterIncrement();
/*
* We use RESTRICT here for safety, but at present we do not expect
* anything to depend on the default.
*/
RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, true);
StoreAttrDefault(rel, attnum, defaultexpr);
}
/* Cleanup */
heap_freetuple(heapTup);
}
/*
* Cleanup after we've finished all the ALTER TYPE operations for a
* particular relation. We have to drop and recreate all the indexes
* and constraints that depend on the altered columns.
*/
static void
ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab, LOCKMODE lockmode)
{
ObjectAddress obj;
ListCell *l;
/*
* Re-parse the index and constraint definitions, and attach them to the
* appropriate work queue entries. We do this before dropping because in
* the case of a FOREIGN KEY constraint, we might not yet have exclusive
* lock on the table the constraint is attached to, and we need to get
* that before dropping. It's safe because the parser won't actually look
* at the catalogs to detect the existing entry.
*/
foreach(l, tab->changedIndexDefs)
ATPostAlterTypeParse((char *) lfirst(l), wqueue, lockmode);
foreach(l, tab->changedConstraintDefs)
ATPostAlterTypeParse((char *) lfirst(l), wqueue, lockmode);
/*
* Now we can drop the existing constraints and indexes --- constraints
* first, since some of them might depend on the indexes. In fact, we
* have to delete FOREIGN KEY constraints before UNIQUE constraints, but
* we already ordered the constraint list to ensure that would happen. It
* should be okay to use DROP_RESTRICT here, since nothing else should be
* depending on these objects.
*/
foreach(l, tab->changedConstraintOids)
{
obj.classId = ConstraintRelationId;
obj.objectId = lfirst_oid(l);
obj.objectSubId = 0;
performDeletion(&obj, DROP_RESTRICT);
}
foreach(l, tab->changedIndexOids)
{
obj.classId = RelationRelationId; obj.objectId = lfirst_oid(l);
obj.objectSubId = 0;
performDeletion(&obj, DROP_RESTRICT);
}
/*
* The objects will get recreated during subsequent passes over the work
* queue.
*/
}
static void
ATPostAlterTypeParse(char *cmd, List **wqueue, LOCKMODE lockmode)
{
List *raw_parsetree_list;
List *querytree_list;
ListCell *list_item;
/*
* We expect that we will get only ALTER TABLE and CREATE INDEX
* statements. Hence, there is no need to pass them through
* parse_analyze() or the rewriter, but instead we need to pass them
* through parse_utilcmd.c to make them ready for execution.
*/
raw_parsetree_list = raw_parser(cmd);
querytree_list = NIL;
foreach(list_item, raw_parsetree_list)
{
Node *stmt = (Node *) lfirst(list_item);
if (IsA(stmt, IndexStmt))
querytree_list = lappend(querytree_list,
transformIndexStmt((IndexStmt *) stmt,
cmd));
else if (IsA(stmt, AlterTableStmt))
querytree_list = list_concat(querytree_list,
transformAlterTableStmt((AlterTableStmt *) stmt,
cmd));
else
querytree_list = lappend(querytree_list, stmt);
}
/*
* Attach each generated command to the proper place in the work queue.
* Note this could result in creation of entirely new work-queue entries.
*/
foreach(list_item, querytree_list)
{
Node *stm = (Node *) lfirst(list_item);
Relation rel;
AlteredTableInfo *tab;
switch (nodeTag(stm))
{
case T_IndexStmt:
{
IndexStmt *stmt = (IndexStmt *) stm;
AlterTableCmd *newcmd;
rel = relation_openrv(stmt->relation, lockmode);
tab = ATGetQueueEntry(wqueue, rel);
newcmd = makeNode(AlterTableCmd);
newcmd->subtype = AT_ReAddIndex;
newcmd->def = (Node *) stmt;
tab->subcmds[AT_PASS_OLD_INDEX] =
lappend(tab->subcmds[AT_PASS_OLD_INDEX], newcmd);
relation_close(rel, NoLock);
break;
}
case T_AlterTableStmt: {
AlterTableStmt *stmt = (AlterTableStmt *) stm;
ListCell *lcmd;
rel = relation_openrv(stmt->relation, lockmode);
tab = ATGetQueueEntry(wqueue, rel);
foreach(lcmd, stmt->cmds)
{
AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
switch (cmd->subtype)
{
case AT_AddIndex:
cmd->subtype = AT_ReAddIndex;
tab->subcmds[AT_PASS_OLD_INDEX] =
lappend(tab->subcmds[AT_PASS_OLD_INDEX], cmd);
break;
case AT_AddConstraint:
tab->subcmds[AT_PASS_OLD_CONSTR] =
lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd);
break;
default:
elog(ERROR, "unexpected statement type: %d",
(int) cmd->subtype);
}
}
relation_close(rel, NoLock);
break;
}
default:
elog(ERROR, "unexpected statement type: %d",
(int) nodeTag(stm));
}
}
}
/*
* ALTER TABLE OWNER
*
* recursing is true if we are recursing from a table to its indexes,
* sequences, or toast table. We don't allow the ownership of those things to
* be changed separately from the parent table. Also, we can skip permission
* checks (this is necessary not just an optimization, else we'd fail to
* handle toast tables properly).
*
* recursing is also true if ALTER TYPE OWNER is calling us to fix up a
* free-standing composite type.
*/
void
ATExecChangeOwner(Oid relationOid, Oid newOwnerId, bool recursing, LOCKMODE lockmode)
{
Relation target_rel;
Relation class_rel;
HeapTuple tuple;
Form_pg_class tuple_class;
/*
* Get exclusive lock till end of transaction on the target table. Use
* relation_open so that we can work on indexes and sequences.
*/
target_rel = relation_open(relationOid, lockmode);
/* Get its pg_class tuple, too */
class_rel = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relationOid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relationOid);
tuple_class = (Form_pg_class) GETSTRUCT(tuple);
/* Can we change the ownership of this tuple? */
switch (tuple_class->relkind)
{
case RELKIND_RELATION:
case RELKIND_VIEW:
/* ok to change owner */
break;
case RELKIND_INDEX:
if (!recursing)
{
/*
* Because ALTER INDEX OWNER used to be allowed, and in fact
* is generated by old versions of pg_dump, we give a warning
* and do nothing rather than erroring out. Also, to avoid
* unnecessary chatter while restoring those old dumps, say
* nothing at all if the command would be a no-op anyway.
*/
if (tuple_class->relowner != newOwnerId)
ereport(WARNING,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot change owner of index \"%s\"",
NameStr(tuple_class->relname)),
errhint("Change the ownership of the index's table, instead.")));
/* quick hack to exit via the no-op path */
newOwnerId = tuple_class->relowner;
}
break;
case RELKIND_SEQUENCE:
if (!recursing &&
tuple_class->relowner != newOwnerId)
{
/* if it's an owned sequence, disallow changing it by itself */
Oid tableId;
int32 colId;
if (sequenceIsOwned(relationOid, &tableId, &colId))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot change owner of sequence \"%s\"",
NameStr(tuple_class->relname)),
errdetail("Sequence \"%s\" is linked to table \"%s\".",
NameStr(tuple_class->relname),
get_rel_name(tableId))));
}
break;
case RELKIND_COMPOSITE_TYPE:
if (recursing)
break;
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a composite type",
NameStr(tuple_class->relname)),
errhint("Use ALTER TYPE instead.")));
break;
case RELKIND_TOASTVALUE:
if (recursing)
break;
/* FALL THRU */
default:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table, view, or sequence",
NameStr(tuple_class->relname))));
}
/*
* If the new owner is the same as the existing owner, consider the
* command to have succeeded. This is for dump restoration purposes.
*/ if (tuple_class->relowner != newOwnerId)
{
Datum repl_val[Natts_pg_class];
bool repl_null[Natts_pg_class];
bool repl_repl[Natts_pg_class];
Acl *newAcl;
Datum aclDatum;
bool isNull;
HeapTuple newtuple;
/* skip permission checks when recursing to index or toast table */
if (!recursing)
{
/* Superusers can always do it */
if (!superuser())
{
Oid namespaceOid = tuple_class->relnamespace;
AclResult aclresult;
/* Otherwise, must be owner of the existing object */
if (!pg_class_ownercheck(relationOid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(target_rel));
/* Must be able to become new owner */
check_is_member_of_role(GetUserId(), newOwnerId);
/* New owner must have CREATE privilege on namespace */
aclresult = pg_namespace_aclcheck(namespaceOid, newOwnerId,
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
get_namespace_name(namespaceOid));
}
}
memset(repl_null, false, sizeof(repl_null));
memset(repl_repl, false, sizeof(repl_repl));
repl_repl[Anum_pg_class_relowner - 1] = true;
repl_val[Anum_pg_class_relowner - 1] = ObjectIdGetDatum(newOwnerId);
/*
* Determine the modified ACL for the new owner. This is only
* necessary when the ACL is non-null.
*/
aclDatum = SysCacheGetAttr(RELOID, tuple,
Anum_pg_class_relacl,
&isNull);
if (!isNull)
{
newAcl = aclnewowner(DatumGetAclP(aclDatum),
tuple_class->relowner, newOwnerId);
repl_repl[Anum_pg_class_relacl - 1] = true;
repl_val[Anum_pg_class_relacl - 1] = PointerGetDatum(newAcl);
}
newtuple = heap_modify_tuple(tuple, RelationGetDescr(class_rel), repl_val, repl_null, repl_repl);
simple_heap_update(class_rel, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(class_rel, newtuple);
heap_freetuple(newtuple);
/*
* Update owner dependency reference, if any. A composite type has
* none, because it's tracked for the pg_type entry instead of here;
* indexes and TOAST tables don't have their own entries either.
*/
if (tuple_class->relkind != RELKIND_COMPOSITE_TYPE && tuple_class->relkind != RELKIND_INDEX &&
tuple_class->relkind != RELKIND_TOASTVALUE)
changeDependencyOnOwner(RelationRelationId, relationOid,
newOwnerId);
/*
* Also change the ownership of the table's rowtype, if it has one
*/
if (tuple_class->relkind != RELKIND_INDEX)
AlterTypeOwnerInternal(tuple_class->reltype, newOwnerId,
tuple_class->relkind == RELKIND_COMPOSITE_TYPE);
/*
* If we are operating on a table, also change the ownership of any
* indexes and sequences that belong to the table, as well as the
* table's toast table (if it has one)
*/
if (tuple_class->relkind == RELKIND_RELATION ||
tuple_class->relkind == RELKIND_TOASTVALUE)
{
List *index_oid_list;
ListCell *i;
/* Find all the indexes belonging to this relation */
index_oid_list = RelationGetIndexList(target_rel);
/* For each index, recursively change its ownership */
foreach(i, index_oid_list)
ATExecChangeOwner(lfirst_oid(i), newOwnerId, true, lockmode);
list_free(index_oid_list);
}
if (tuple_class->relkind == RELKIND_RELATION)
{
/* If it has a toast table, recurse to change its ownership */
if (tuple_class->reltoastrelid != InvalidOid)
ATExecChangeOwner(tuple_class->reltoastrelid, newOwnerId,
true, lockmode);
/* If it has dependent sequences, recurse to change them too */
change_owner_recurse_to_sequences(relationOid, newOwnerId, lockmode);
}
}
ReleaseSysCache(tuple);
heap_close(class_rel, RowExclusiveLock);
relation_close(target_rel, NoLock);
}
/*
* change_owner_recurse_to_sequences
*
* Helper function for ATExecChangeOwner. Examines pg_depend searching
* for sequences that are dependent on serial columns, and changes their
* ownership.
*/
static void
change_owner_recurse_to_sequences(Oid relationOid, Oid newOwnerId, LOCKMODE lockmode)
{
Relation depRel;
SysScanDesc scan;
ScanKeyData key[2];
HeapTuple tup;
/*
* SERIAL sequences are those having an auto dependency on one of the
* table's columns (we don't care *which* column, exactly).
*/
depRel = heap_open(DependRelationId, AccessShareLock);
ScanKeyInit(&key[0],
Anum_pg_depend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relationOid));
/* we leave refobjsubid unspecified */
scan = systable_beginscan(depRel, DependReferenceIndexId, true,
SnapshotNow, 2, key);
while (HeapTupleIsValid(tup = systable_getnext(scan)))
{
Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
Relation seqRel;
/* skip dependencies other than auto dependencies on columns */
if (depForm->refobjsubid == 0 ||
depForm->classid != RelationRelationId ||
depForm->objsubid != 0 ||
depForm->deptype != DEPENDENCY_AUTO)
continue;
/* Use relation_open just in case it's an index */
seqRel = relation_open(depForm->objid, lockmode);
/* skip non-sequence relations */
if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE)
{
/* No need to keep the lock */
relation_close(seqRel, lockmode);
continue;
}
/* We don't need to close the sequence while we alter it. */
ATExecChangeOwner(depForm->objid, newOwnerId, true, lockmode);
/* Now we can close it. Keep the lock till end of transaction. */
relation_close(seqRel, NoLock);
}
systable_endscan(scan);
relation_close(depRel, AccessShareLock);
}
/*
* ALTER TABLE CLUSTER ON
*
* The only thing we have to do is to change the indisclustered bits.
*/
static void
ATExecClusterOn(Relation rel, const char *indexName, LOCKMODE lockmode)
{
Oid indexOid;
indexOid = get_relname_relid(indexName, rel->rd_rel->relnamespace);
if (!OidIsValid(indexOid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("index \"%s\" for table \"%s\" does not exist",
indexName, RelationGetRelationName(rel))));
/* Check index is valid to cluster on */
check_index_is_clusterable(rel, indexOid, false, lockmode);
/* And do the work */
mark_index_clustered(rel, indexOid);
}
/*
* ALTER TABLE SET WITHOUT CLUSTER
*
* We have to find any indexes on the table that have indisclustered bit
* set and turn it off.
*/
static void
ATExecDropCluster(Relation rel, LOCKMODE lockmode)
{
mark_index_clustered(rel, InvalidOid);
}
/*
* ALTER TABLE SET TABLESPACE
*/
static void
ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, char *tablespacename, LOCKMODE lockmode)
{
Oid tablespaceId;
AclResult aclresult;
/* Check that the tablespace exists */
tablespaceId = get_tablespace_oid(tablespacename, false);
/* Check its permissions */
aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_TABLESPACE, tablespacename);
/* Save info for Phase 3 to do the real work */
if (OidIsValid(tab->newTableSpace))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("cannot have multiple SET TABLESPACE subcommands")));
tab->newTableSpace = tablespaceId;
}
/*
* ALTER TABLE/INDEX SET (...) or RESET (...)
*/
static void
ATExecSetRelOptions(Relation rel, List *defList, bool isReset, LOCKMODE lockmode)
{
Oid relid;
Relation pgclass;
HeapTuple tuple;
HeapTuple newtuple;
Datum datum;
bool isnull;
Datum newOptions;
Datum repl_val[Natts_pg_class];
bool repl_null[Natts_pg_class];
bool repl_repl[Natts_pg_class];
static char *validnsps[] = HEAP_RELOPT_NAMESPACES;
if (defList == NIL)
return; /* nothing to do */
pgclass = heap_open(RelationRelationId, RowExclusiveLock);
/* Get the old reloptions */
relid = RelationGetRelid(rel);
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relid);
datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions, &isnull);
/* Generate new proposed reloptions (text array) */
newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
defList, NULL, validnsps, false, isReset);
/* Validate */
switch (rel->rd_rel->relkind)
{
case RELKIND_RELATION:
case RELKIND_TOASTVALUE:
(void) heap_reloptions(rel->rd_rel->relkind, newOptions, true);
break;
case RELKIND_INDEX:
(void) index_reloptions(rel->rd_am->amoptions, newOptions, true);
break;
default:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table, index, or TOAST table",
RelationGetRelationName(rel))));
break;
}
/*
* All we need do here is update the pg_class row; the new options will be
* propagated into relcaches during post-commit cache inval.
*/
memset(repl_val, 0, sizeof(repl_val));
memset(repl_null, false, sizeof(repl_null));
memset(repl_repl, false, sizeof(repl_repl));
if (newOptions != (Datum) 0)
repl_val[Anum_pg_class_reloptions - 1] = newOptions;
else
repl_null[Anum_pg_class_reloptions - 1] = true;
repl_repl[Anum_pg_class_reloptions - 1] = true;
newtuple = heap_modify_tuple(tuple, RelationGetDescr(pgclass),
repl_val, repl_null, repl_repl);
simple_heap_update(pgclass, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(pgclass, newtuple);
heap_freetuple(newtuple);
ReleaseSysCache(tuple);
/* repeat the whole exercise for the toast table, if there's one */
if (OidIsValid(rel->rd_rel->reltoastrelid))
{
Relation toastrel;
Oid toastid = rel->rd_rel->reltoastrelid;
toastrel = heap_open(toastid, lockmode);
/* Get the old reloptions */
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(toastid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", toastid);
datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions, &isnull);
newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
defList, "toast", validnsps, false, isReset);
(void) heap_reloptions(RELKIND_TOASTVALUE, newOptions, true);
memset(repl_val, 0, sizeof(repl_val));
memset(repl_null, false, sizeof(repl_null));
memset(repl_repl, false, sizeof(repl_repl));
if (newOptions != (Datum) 0)
repl_val[Anum_pg_class_reloptions - 1] = newOptions;
else
repl_null[Anum_pg_class_reloptions - 1] = true;
repl_repl[Anum_pg_class_reloptions - 1] = true;
newtuple = heap_modify_tuple(tuple, RelationGetDescr(pgclass),
repl_val, repl_null, repl_repl);
simple_heap_update(pgclass, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(pgclass, newtuple);
heap_freetuple(newtuple);
ReleaseSysCache(tuple);
heap_close(toastrel, NoLock);
}
heap_close(pgclass, RowExclusiveLock);
}
/*
* Execute ALTER TABLE SET TABLESPACE for cases where there is no tuple
* rewriting to be done, so we just want to copy the data as fast as possible.
*/
static void
ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
{
Relation rel;
Oid oldTableSpace;
Oid reltoastrelid;
Oid reltoastidxid;
Oid newrelfilenode;
RelFileNode newrnode;
SMgrRelation dstrel;
Relation pg_class;
HeapTuple tuple;
Form_pg_class rd_rel;
ForkNumber forkNum;
/*
* Need lock here in case we are recursing to toast table or index
*/
rel = relation_open(tableOid, lockmode);
/*
* No work if no change in tablespace.
*/
oldTableSpace = rel->rd_rel->reltablespace;
if (newTableSpace == oldTableSpace ||
(newTableSpace == MyDatabaseTableSpace && oldTableSpace == 0))
{
relation_close(rel, NoLock);
return;
}
/*
* We cannot support moving mapped relations into different tablespaces.
* (In particular this eliminates all shared catalogs.)
*/
if (RelationIsMapped(rel))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot move system relation \"%s\"",
RelationGetRelationName(rel))));
/* Can't move a non-shared relation into pg_global */
if (newTableSpace == GLOBALTABLESPACE_OID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("only shared relations can be placed in pg_global tablespace")));
/*
* Don't allow moving temp tables of other backends ... their local buffer
* manager is not going to cope.
*/
if (RELATION_IS_OTHER_TEMP(rel))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move temporary tables of other sessions")));
reltoastrelid = rel->rd_rel->reltoastrelid;
reltoastidxid = rel->rd_rel->reltoastidxid;
/* Get a modifiable copy of the relation's pg_class row */
pg_class = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(tableOid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", tableOid);
rd_rel = (Form_pg_class) GETSTRUCT(tuple);
/*
* Since we copy the file directly without looking at the shared buffers,
* we'd better first flush out any pages of the source relation that are
* in shared buffers. We assume no new changes will be made while we are
* holding exclusive lock on the rel.
*/
FlushRelationBuffers(rel);
/*
* Relfilenodes are not unique across tablespaces, so we need to allocate
* a new one in the new tablespace.
*/
newrelfilenode = GetNewRelFileNode(newTableSpace, NULL, rel->rd_backend);
/* Open old and new relation */
newrnode = rel->rd_node;
newrnode.relNode = newrelfilenode;
newrnode.spcNode = newTableSpace;
dstrel = smgropen(newrnode, rel->rd_backend);
RelationOpenSmgr(rel);
/*
* Create and copy all forks of the relation, and schedule unlinking of
* old physical files.
*
* NOTE: any conflict in relfilenode value will be caught in
* RelationCreateStorage().
*/
RelationCreateStorage(newrnode, rel->rd_istemp);
/* copy main fork */
copy_relation_data(rel->rd_smgr, dstrel, MAIN_FORKNUM, rel->rd_istemp);
/* copy those extra forks that exist */
for (forkNum = MAIN_FORKNUM + 1; forkNum <= MAX_FORKNUM; forkNum++)
{
if (smgrexists(rel->rd_smgr, forkNum))
{
smgrcreate(dstrel, forkNum, false);
copy_relation_data(rel->rd_smgr, dstrel, forkNum, rel->rd_istemp); }
}
/* drop old relation, and close new one */
RelationDropStorage(rel);
smgrclose(dstrel);
/* update the pg_class row */
rd_rel->reltablespace = (newTableSpace == MyDatabaseTableSpace) ? InvalidOid : newTableSpace;
rd_rel->relfilenode = newrelfilenode;
simple_heap_update(pg_class, &tuple->t_self, tuple);
CatalogUpdateIndexes(pg_class, tuple);
heap_freetuple(tuple);
heap_close(pg_class, RowExclusiveLock);
relation_close(rel, NoLock);
/* Make sure the reltablespace change is visible */
CommandCounterIncrement();
/* Move associated toast relation and/or index, too */
if (OidIsValid(reltoastrelid))
ATExecSetTableSpace(reltoastrelid, newTableSpace, lockmode);
if (OidIsValid(reltoastidxid))
ATExecSetTableSpace(reltoastidxid, newTableSpace, lockmode);
}
/*
* Copy data, block by block
*/
static void
copy_relation_data(SMgrRelation src, SMgrRelation dst,
ForkNumber forkNum, bool istemp)
{
char *buf;
Page page;
bool use_wal;
BlockNumber nblocks;
BlockNumber blkno;
/*
* palloc the buffer so that it's MAXALIGN'd. If it were just a local
* char[] array, the compiler might align it on any byte boundary, which
* can seriously hurt transfer speed to and from the kernel; not to
* mention possibly making log_newpage's accesses to the page header fail.
*/
buf = (char *) palloc(BLCKSZ);
page = (Page) buf;
/*
* We need to log the copied data in WAL iff WAL archiving/streaming is
* enabled AND it's not a temp rel.
*/
use_wal = XLogIsNeeded() && !istemp;
nblocks = smgrnblocks(src, forkNum);
for (blkno = 0; blkno < nblocks; blkno++)
{
/* If we got a cancel signal during the copy of the data, quit */
CHECK_FOR_INTERRUPTS();
smgrread(src, forkNum, blkno, buf);
/* XLOG stuff */
if (use_wal)
log_newpage(&dst->smgr_rnode.node, forkNum, blkno, page);
/*
* Now write the page. We say isTemp = true even if it's not a temp
* rel, because there's no need for smgr to schedule an fsync for this
* write; we'll do it ourselves below.
*/
smgrextend(dst, forkNum, blkno, buf, true);
}
pfree(buf);
/*
* If the rel isn't temp, we must fsync it down to disk before it's safe
* to commit the transaction. (For a temp rel we don't care since the rel
* will be uninteresting after a crash anyway.)
*
* It's obvious that we must do this when not WAL-logging the copy. It's
* less obvious that we have to do it even if we did WAL-log the copied
* pages. The reason is that since we're copying outside shared buffers, a
* CHECKPOINT occurring during the copy has no way to flush the previously
* written data to disk (indeed it won't know the new rel even exists). A
* crash later on would replay WAL from the checkpoint, therefore it
* wouldn't replay our earlier WAL entries. If we do not fsync those pages
* here, they might still not be on disk when the crash occurs.
*/
if (!istemp)
smgrimmedsync(dst, forkNum);
}
/*
* ALTER TABLE ENABLE/DISABLE TRIGGER
*
* We just pass this off to trigger.c.
*/
static void
ATExecEnableDisableTrigger(Relation rel, char *trigname,
char fires_when, bool skip_system, LOCKMODE lockmode)
{
EnableDisableTrigger(rel, trigname, fires_when, skip_system);
}
/*
* ALTER TABLE ENABLE/DISABLE RULE
*
* We just pass this off to rewriteDefine.c.
*/
static void
ATExecEnableDisableRule(Relation rel, char *trigname,
char fires_when, LOCKMODE lockmode)
{
EnableDisableRule(rel, trigname, fires_when);
}
/*
* ALTER TABLE INHERIT
*
* Add a parent to the child's parents. This verifies that all the columns and
* check constraints of the parent appear in the child and that they have the
* same data types and expressions.
*/
static void
ATPrepAddInherit(Relation child_rel)
{
if (child_rel->rd_rel->reloftype)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot change inheritance of typed table")));
}
static void
ATExecAddInherit(Relation child_rel, RangeVar *parent, LOCKMODE lockmode){
Relation parent_rel,
catalogRelation;
SysScanDesc scan;
ScanKeyData key;
HeapTuple inheritsTuple;
int32 inhseqno;
List *children;
/*
* AccessShareLock on the parent is what's obtained during normal CREATE
* TABLE ... INHERITS ..., so should be enough here.
*/
parent_rel = heap_openrv(parent, AccessShareLock);
/*
* Must be owner of both parent and child -- child was checked by
* ATSimplePermissions call in ATPrepCmd
*/
ATSimplePermissions(parent_rel, false);
/* Permanent rels cannot inherit from temporary ones */
if (parent_rel->rd_istemp && !child_rel->rd_istemp)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot inherit from temporary relation \"%s\"",
RelationGetRelationName(parent_rel))));
/*
* Check for duplicates in the list of parents, and determine the highest
* inhseqno already present; we'll use the next one for the new parent.
* (Note: get RowExclusiveLock because we will write pg_inherits below.)
*
* Note: we do not reject the case where the child already inherits from
* the parent indirectly; CREATE TABLE doesn't reject comparable cases.
*/
catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
ScanKeyInit(&key,
Anum_pg_inherits_inhrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(child_rel)));
scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId,
true, SnapshotNow, 1, &key);
/* inhseqno sequences start at 1 */
inhseqno = 0;
while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
{
Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inheritsTuple);
if (inh->inhparent == RelationGetRelid(parent_rel))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" would be inherited from more than once",
RelationGetRelationName(parent_rel))));
if (inh->inhseqno > inhseqno)
inhseqno = inh->inhseqno;
}
systable_endscan(scan);
/*
* Prevent circularity by seeing if proposed parent inherits from child.
* (In particular, this disallows making a rel inherit from itself.)
*
* This is not completely bulletproof because of race conditions: in
* multi-level inheritance trees, someone else could concurrently be
* making another inheritance link that closes the loop but does not join
* either of the rels we have locked. Preventing that seems to require
* exclusive locks on the entire inheritance tree, which is a cure worse
* than the disease. find_all_inheritors() will cope with circularity * anyway, so don't sweat it too much.
*
* We use weakest lock we can on child's children, namely AccessShareLock.
*/
children = find_all_inheritors(RelationGetRelid(child_rel),
AccessShareLock, NULL);
if (list_member_oid(children, RelationGetRelid(parent_rel)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("circular inheritance not allowed"),
errdetail("\"%s\" is already a child of \"%s\".",
parent->relname,
RelationGetRelationName(child_rel))));
/* If parent has OIDs then child must have OIDs */
if (parent_rel->rd_rel->relhasoids && !child_rel->rd_rel->relhasoids)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("table \"%s\" without OIDs cannot inherit from table \"%s\" with OIDs",
RelationGetRelationName(child_rel),
RelationGetRelationName(parent_rel))));
/* Match up the columns and bump attinhcount as needed */
MergeAttributesIntoExisting(child_rel, parent_rel);
/* Match up the constraints and bump coninhcount as needed */
MergeConstraintsIntoExisting(child_rel, parent_rel);
/*
* OK, it looks valid. Make the catalog entries that show inheritance.
*/
StoreCatalogInheritance1(RelationGetRelid(child_rel),
RelationGetRelid(parent_rel),
inhseqno + 1,
catalogRelation);
/* Now we're done with pg_inherits */
heap_close(catalogRelation, RowExclusiveLock);
/* keep our lock on the parent relation until commit */
heap_close(parent_rel, NoLock);
}
/*
* Obtain the source-text form of the constraint expression for a check
* constraint, given its pg_constraint tuple
*/
static char *
decompile_conbin(HeapTuple contup, TupleDesc tupdesc)
{
Form_pg_constraint con;
bool isnull;
Datum attr;
Datum expr;
con = (Form_pg_constraint) GETSTRUCT(contup);
attr = heap_getattr(contup, Anum_pg_constraint_conbin, tupdesc, &isnull);
if (isnull)
elog(ERROR, "null conbin for constraint %u", HeapTupleGetOid(contup));
expr = DirectFunctionCall2(pg_get_expr, attr,
ObjectIdGetDatum(con->conrelid));
return TextDatumGetCString(expr);
}
/*
* Determine whether two check constraints are functionally equivalent
*
* The test we apply is to see whether they reverse-compile to the same * source string. This insulates us from issues like whether attributes
* have the same physical column numbers in parent and child relations.
*/
static bool
constraints_equivalent(HeapTuple a, HeapTuple b, TupleDesc tupleDesc)
{
Form_pg_constraint acon = (Form_pg_constraint) GETSTRUCT(a);
Form_pg_constraint bcon = (Form_pg_constraint) GETSTRUCT(b);
if (acon->condeferrable != bcon->condeferrable ||
acon->condeferred != bcon->condeferred ||
strcmp(decompile_conbin(a, tupleDesc),
decompile_conbin(b, tupleDesc)) != 0)
return false;
else
return true;
}
/*
* Check columns in child table match up with columns in parent, and increment
* their attinhcount.
*
* Called by ATExecAddInherit
*
* Currently all parent columns must be found in child. Missing columns are an
* error. One day we might consider creating new columns like CREATE TABLE
* does. However, that is widely unpopular --- in the common use case of
* partitioned tables it's a foot-gun.
*
* The data type must match exactly. If the parent column is NOT NULL then
* the child must be as well. Defaults are not compared, however.
*/
static void
MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel)
{
Relation attrrel;
AttrNumber parent_attno;
int parent_natts;
TupleDesc tupleDesc;
TupleConstr *constr;
HeapTuple tuple;
attrrel = heap_open(AttributeRelationId, RowExclusiveLock);
tupleDesc = RelationGetDescr(parent_rel);
parent_natts = tupleDesc->natts;
constr = tupleDesc->constr;
for (parent_attno = 1; parent_attno <= parent_natts; parent_attno++)
{
Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
char *attributeName = NameStr(attribute->attname);
/* Ignore dropped columns in the parent. */
if (attribute->attisdropped)
continue;
/* Find same column in child (matching on column name). */
tuple = SearchSysCacheCopyAttName(RelationGetRelid(child_rel),
attributeName);
if (HeapTupleIsValid(tuple))
{
/* Check they are same type and typmod */
Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
if (attribute->atttypid != childatt->atttypid ||
attribute->atttypmod != childatt->atttypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table \"%s\" has different type for column \"%s\"", RelationGetRelationName(child_rel),
attributeName)));
if (attribute->attnotnull && !childatt->attnotnull)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" in child table must be marked NOT NULL",
attributeName)));
/*
* OK, bump the child column's inheritance count. (If we fail
* later on, this change will just roll back.)
*/
childatt->attinhcount++;
simple_heap_update(attrrel, &tuple->t_self, tuple);
CatalogUpdateIndexes(attrrel, tuple);
heap_freetuple(tuple);
}
else
{
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table is missing column \"%s\"",
attributeName)));
}
}
heap_close(attrrel, RowExclusiveLock);
}
/*
* Check constraints in child table match up with constraints in parent,
* and increment their coninhcount.
*
* Called by ATExecAddInherit
*
* Currently all constraints in parent must be present in the child. One day we
* may consider adding new constraints like CREATE TABLE does. We may also want
* to allow an optional flag on parent table constraints indicating they are
* intended to ONLY apply to the master table, not to the children. That would
* make it possible to ensure no records are mistakenly inserted into the
* master in partitioned tables rather than the appropriate child.
*
* XXX This is O(N^2) which may be an issue with tables with hundreds of
* constraints. As long as tables have more like 10 constraints it shouldn't be
* a problem though. Even 100 constraints ought not be the end of the world.
*/
static void
MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel)
{
Relation catalog_relation;
TupleDesc tuple_desc;
SysScanDesc parent_scan;
ScanKeyData parent_key;
HeapTuple parent_tuple;
catalog_relation = heap_open(ConstraintRelationId, RowExclusiveLock);
tuple_desc = RelationGetDescr(catalog_relation);
/* Outer loop scans through the parent's constraint definitions */
ScanKeyInit(&parent_key,
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(parent_rel)));
parent_scan = systable_beginscan(catalog_relation, ConstraintRelidIndexId,
true, SnapshotNow, 1, &parent_key);
while (HeapTupleIsValid(parent_tuple = systable_getnext(parent_scan)))
{
Form_pg_constraint parent_con = (Form_pg_constraint) GETSTRUCT(parent_tuple); SysScanDesc child_scan;
ScanKeyData child_key;
HeapTuple child_tuple;
bool found = false;
if (parent_con->contype != CONSTRAINT_CHECK)
continue;
/* Search for a child constraint matching this one */
ScanKeyInit(&child_key,
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(child_rel)));
child_scan = systable_beginscan(catalog_relation, ConstraintRelidIndexId,
true, SnapshotNow, 1, &child_key);
while (HeapTupleIsValid(child_tuple = systable_getnext(child_scan)))
{
Form_pg_constraint child_con = (Form_pg_constraint) GETSTRUCT(child_tuple);
HeapTuple child_copy;
if (child_con->contype != CONSTRAINT_CHECK)
continue;
if (strcmp(NameStr(parent_con->conname),
NameStr(child_con->conname)) != 0)
continue;
if (!constraints_equivalent(parent_tuple, child_tuple, tuple_desc))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table \"%s\" has different definition for check constraint \"%s\"",
RelationGetRelationName(child_rel),
NameStr(parent_con->conname))));
/*
* OK, bump the child constraint's inheritance count. (If we fail
* later on, this change will just roll back.)
*/
child_copy = heap_copytuple(child_tuple);
child_con = (Form_pg_constraint) GETSTRUCT(child_copy);
child_con->coninhcount++;
simple_heap_update(catalog_relation, &child_copy->t_self, child_copy);
CatalogUpdateIndexes(catalog_relation, child_copy);
heap_freetuple(child_copy);
found = true;
break;
}
systable_endscan(child_scan);
if (!found)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table is missing constraint \"%s\"",
NameStr(parent_con->conname))));
}
systable_endscan(parent_scan);
heap_close(catalog_relation, RowExclusiveLock);
}
/*
* ALTER TABLE NO INHERIT
*
* Drop a parent from the child's parents. This just adjusts the attinhcount
* and attislocal of the columns and removes the pg_inherit and pg_depend
* entries.
* * If attinhcount goes to 0 then attislocal gets set to true. If it goes back
* up attislocal stays true, which means if a child is ever removed from a
* parent then its columns will never be automatically dropped which may
* surprise. But at least we'll never surprise by dropping columns someone
* isn't expecting to be dropped which would actually mean data loss.
*
* coninhcount and conislocal for inherited constraints are adjusted in
* exactly the same way.
*/
static void
ATExecDropInherit(Relation rel, RangeVar *parent, LOCKMODE lockmode)
{
Relation parent_rel;
Relation catalogRelation;
SysScanDesc scan;
ScanKeyData key[3];
HeapTuple inheritsTuple,
attributeTuple,
constraintTuple,
depTuple;
List *connames;
bool found = false;
/*
* AccessShareLock on the parent is probably enough, seeing that DROP
* TABLE doesn't lock parent tables at all. We need some lock since we'll
* be inspecting the parent's schema.
*/
parent_rel = heap_openrv(parent, AccessShareLock);
/*
* We don't bother to check ownership of the parent table --- ownership of
* the child is presumed enough rights.
*/
/*
* Find and destroy the pg_inherits entry linking the two, or error out if
* there is none.
*/
catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_inherits_inhrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId,
true, SnapshotNow, 1, key);
while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
{
Oid inhparent;
inhparent = ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhparent;
if (inhparent == RelationGetRelid(parent_rel))
{
simple_heap_delete(catalogRelation, &inheritsTuple->t_self);
found = true;
break;
}
}
systable_endscan(scan);
heap_close(catalogRelation, RowExclusiveLock);
if (!found)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" is not a parent of relation \"%s\"",
RelationGetRelationName(parent_rel),
RelationGetRelationName(rel))));
/*
* Search through child columns looking for ones matching parent rel
*/
catalogRelation = heap_open(AttributeRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_attribute_attrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
scan = systable_beginscan(catalogRelation, AttributeRelidNumIndexId,
true, SnapshotNow, 1, key);
while (HeapTupleIsValid(attributeTuple = systable_getnext(scan)))
{
Form_pg_attribute att = (Form_pg_attribute) GETSTRUCT(attributeTuple);
/* Ignore if dropped or not inherited */
if (att->attisdropped)
continue;
if (att->attinhcount <= 0)
continue;
if (SearchSysCacheExistsAttName(RelationGetRelid(parent_rel),
NameStr(att->attname)))
{
/* Decrement inhcount and possibly set islocal to true */
HeapTuple copyTuple = heap_copytuple(attributeTuple);
Form_pg_attribute copy_att = (Form_pg_attribute) GETSTRUCT(copyTuple);
copy_att->attinhcount--;
if (copy_att->attinhcount == 0)
copy_att->attislocal = true;
simple_heap_update(catalogRelation, ©Tuple->t_self, copyTuple);
CatalogUpdateIndexes(catalogRelation, copyTuple);
heap_freetuple(copyTuple);
}
}
systable_endscan(scan);
heap_close(catalogRelation, RowExclusiveLock);
/*
* Likewise, find inherited check constraints and disinherit them. To do
* this, we first need a list of the names of the parent's check
* constraints. (We cheat a bit by only checking for name matches,
* assuming that the expressions will match.)
*/
catalogRelation = heap_open(ConstraintRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(parent_rel)));
scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId,
true, SnapshotNow, 1, key);
connames = NIL;
while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
{
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(constraintTuple);
if (con->contype == CONSTRAINT_CHECK)
connames = lappend(connames, pstrdup(NameStr(con->conname)));
}
systable_endscan(scan);
/* Now scan the child's constraints */
ScanKeyInit(&key[0],
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel))); scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId,
true, SnapshotNow, 1, key);
while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
{
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(constraintTuple);
bool match;
ListCell *lc;
if (con->contype != CONSTRAINT_CHECK)
continue;
match = false;
foreach(lc, connames)
{
if (strcmp(NameStr(con->conname), (char *) lfirst(lc)) == 0)
{
match = true;
break;
}
}
if (match)
{
/* Decrement inhcount and possibly set islocal to true */
HeapTuple copyTuple = heap_copytuple(constraintTuple);
Form_pg_constraint copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
if (copy_con->coninhcount <= 0) /* shouldn't happen */
elog(ERROR, "relation %u has non-inherited constraint \"%s\"",
RelationGetRelid(rel), NameStr(copy_con->conname));
copy_con->coninhcount--;
if (copy_con->coninhcount == 0)
copy_con->conislocal = true;
simple_heap_update(catalogRelation, ©Tuple->t_self, copyTuple);
CatalogUpdateIndexes(catalogRelation, copyTuple);
heap_freetuple(copyTuple);
}
}
systable_endscan(scan);
heap_close(catalogRelation, RowExclusiveLock);
/*
* Drop the dependency
*
* There's no convenient way to do this, so go trawling through pg_depend
*/
catalogRelation = heap_open(DependRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_depend_classid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_objid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
ScanKeyInit(&key[2],
Anum_pg_depend_objsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum(0));
scan = systable_beginscan(catalogRelation, DependDependerIndexId, true,
SnapshotNow, 3, key);
while (HeapTupleIsValid(depTuple = systable_getnext(scan)))
{ Form_pg_depend dep = (Form_pg_depend) GETSTRUCT(depTuple);
if (dep->refclassid == RelationRelationId &&
dep->refobjid == RelationGetRelid(parent_rel) &&
dep->refobjsubid == 0 &&
dep->deptype == DEPENDENCY_NORMAL)
simple_heap_delete(catalogRelation, &depTuple->t_self);
}
systable_endscan(scan);
heap_close(catalogRelation, RowExclusiveLock);
/* keep our lock on the parent relation until commit */
heap_close(parent_rel, NoLock);
}
/*
* Execute ALTER TABLE SET SCHEMA
*
* Note: caller must have checked ownership of the relation already
*/
void
AlterTableNamespace(RangeVar *relation, const char *newschema,
ObjectType stmttype, LOCKMODE lockmode)
{
Relation rel;
Oid relid;
Oid oldNspOid;
Oid nspOid;
Relation classRel;
rel = relation_openrv(relation, lockmode);
relid = RelationGetRelid(rel);
oldNspOid = RelationGetNamespace(rel);
/* Check relation type against type specified in the ALTER command */
switch (stmttype)
{
case OBJECT_TABLE:
/*
* For mostly-historical reasons, we allow ALTER TABLE to apply to
* all relation types.
*/
break;
case OBJECT_SEQUENCE:
if (rel->rd_rel->relkind != RELKIND_SEQUENCE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a sequence",
RelationGetRelationName(rel))));
break;
case OBJECT_VIEW:
if (rel->rd_rel->relkind != RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a view",
RelationGetRelationName(rel))));
break;
default:
elog(ERROR, "unrecognized object type: %d", (int) stmttype);
}
/* Can we change the schema of this tuple? */
switch (rel->rd_rel->relkind) {
case RELKIND_RELATION:
case RELKIND_VIEW:
/* ok to change schema */
break;
case RELKIND_SEQUENCE:
{
/* if it's an owned sequence, disallow moving it by itself */
Oid tableId;
int32 colId;
if (sequenceIsOwned(relid, &tableId, &colId))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move an owned sequence into another schema"),
errdetail("Sequence \"%s\" is linked to table \"%s\".",
RelationGetRelationName(rel),
get_rel_name(tableId))));
}
break;
case RELKIND_COMPOSITE_TYPE:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a composite type",
RelationGetRelationName(rel)),
errhint("Use ALTER TYPE instead.")));
break;
case RELKIND_INDEX:
case RELKIND_TOASTVALUE:
/* FALL THRU */
default:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table, view, or sequence",
RelationGetRelationName(rel))));
}
/* get schema OID and check its permissions */
nspOid = LookupCreationNamespace(newschema);
if (oldNspOid == nspOid)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" is already in schema \"%s\"",
RelationGetRelationName(rel),
newschema)));
/* disallow renaming into or out of temp schemas */
if (isAnyTempNamespace(nspOid) || isAnyTempNamespace(oldNspOid))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move objects into or out of temporary schemas")));
/* same for TOAST schema */
if (nspOid == PG_TOAST_NAMESPACE || oldNspOid == PG_TOAST_NAMESPACE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move objects into or out of TOAST schema")));
/* OK, modify the pg_class row and pg_depend entry */
classRel = heap_open(RelationRelationId, RowExclusiveLock);
AlterRelationNamespaceInternal(classRel, relid, oldNspOid, nspOid, true);
/* Fix the table's rowtype too */
AlterTypeNamespaceInternal(rel->rd_rel->reltype, nspOid, false, false);
/* Fix other dependent stuff */
if (rel->rd_rel->relkind == RELKIND_RELATION)
{ AlterIndexNamespaces(classRel, rel, oldNspOid, nspOid);
AlterSeqNamespaces(classRel, rel, oldNspOid, nspOid, newschema, lockmode);
AlterConstraintNamespaces(relid, oldNspOid, nspOid, false);
}
heap_close(classRel, RowExclusiveLock);
/* close rel, but keep lock until commit */
relation_close(rel, NoLock);
}
/*
* The guts of relocating a relation to another namespace: fix the pg_class
* entry, and the pg_depend entry if any. Caller must already have
* opened and write-locked pg_class.
*/
void
AlterRelationNamespaceInternal(Relation classRel, Oid relOid,
Oid oldNspOid, Oid newNspOid,
bool hasDependEntry)
{
HeapTuple classTup;
Form_pg_class classForm;
classTup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relOid));
if (!HeapTupleIsValid(classTup))
elog(ERROR, "cache lookup failed for relation %u", relOid);
classForm = (Form_pg_class) GETSTRUCT(classTup);
Assert(classForm->relnamespace == oldNspOid);
/* check for duplicate name (more friendly than unique-index failure) */
if (get_relname_relid(NameStr(classForm->relname),
newNspOid) != InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" already exists in schema \"%s\"",
NameStr(classForm->relname),
get_namespace_name(newNspOid))));
/* classTup is a copy, so OK to scribble on */
classForm->relnamespace = newNspOid;
simple_heap_update(classRel, &classTup->t_self, classTup);
CatalogUpdateIndexes(classRel, classTup);
/* Update dependency on schema if caller said so */
if (hasDependEntry &&
changeDependencyFor(RelationRelationId, relOid,
NamespaceRelationId, oldNspOid, newNspOid) != 1)
elog(ERROR, "failed to change schema dependency for relation \"%s\"",
NameStr(classForm->relname));
heap_freetuple(classTup);
}
/*
* Move all indexes for the specified relation to another namespace.
*
* Note: we assume adequate permission checking was done by the caller,
* and that the caller has a suitable lock on the owning relation.
*/
static void
AlterIndexNamespaces(Relation classRel, Relation rel,
Oid oldNspOid, Oid newNspOid)
{
List *indexList;
ListCell *l;
indexList = RelationGetIndexList(rel);
foreach(l, indexList)
{
Oid indexOid = lfirst_oid(l);
/*
* Note: currently, the index will not have its own dependency on the
* namespace, so we don't need to do changeDependencyFor(). There's no
* rowtype in pg_type, either.
*/
AlterRelationNamespaceInternal(classRel, indexOid,
oldNspOid, newNspOid,
false);
}
list_free(indexList);
}
/*
* Move all SERIAL-column sequences of the specified relation to another
* namespace.
*
* Note: we assume adequate permission checking was done by the caller,
* and that the caller has a suitable lock on the owning relation.
*/
static void
AlterSeqNamespaces(Relation classRel, Relation rel,
Oid oldNspOid, Oid newNspOid, const char *newNspName, LOCKMODE lockmode)
{
Relation depRel;
SysScanDesc scan;
ScanKeyData key[2];
HeapTuple tup;
/*
* SERIAL sequences are those having an auto dependency on one of the
* table's columns (we don't care *which* column, exactly).
*/
depRel = heap_open(DependRelationId, AccessShareLock);
ScanKeyInit(&key[0],
Anum_pg_depend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
/* we leave refobjsubid unspecified */
scan = systable_beginscan(depRel, DependReferenceIndexId, true,
SnapshotNow, 2, key);
while (HeapTupleIsValid(tup = systable_getnext(scan)))
{
Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
Relation seqRel;
/* skip dependencies other than auto dependencies on columns */
if (depForm->refobjsubid == 0 ||
depForm->classid != RelationRelationId ||
depForm->objsubid != 0 ||
depForm->deptype != DEPENDENCY_AUTO)
continue;
/* Use relation_open just in case it's an index */
seqRel = relation_open(depForm->objid, lockmode);
/* skip non-sequence relations */
if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE) {
/* No need to keep the lock */
relation_close(seqRel, lockmode);
continue;
}
/* Fix the pg_class and pg_depend entries */
AlterRelationNamespaceInternal(classRel, depForm->objid,
oldNspOid, newNspOid,
true);
/*
* Sequences have entries in pg_type. We need to be careful to move
* them to the new namespace, too.
*/
AlterTypeNamespaceInternal(RelationGetForm(seqRel)->reltype,
newNspOid, false, false);
/* Now we can close it. Keep the lock till end of transaction. */
relation_close(seqRel, NoLock);
}
systable_endscan(scan);
relation_close(depRel, AccessShareLock);
}
/*
* This code supports
* CREATE TEMP TABLE ... ON COMMIT { DROP | PRESERVE ROWS | DELETE ROWS }
*
* Because we only support this for TEMP tables, it's sufficient to remember
* the state in a backend-local data structure.
*/
/*
* Register a newly-created relation's ON COMMIT action.
*/
void
register_on_commit_action(Oid relid, OnCommitAction action)
{
OnCommitItem *oc;
MemoryContext oldcxt;
/*
* We needn't bother registering the relation unless there is an ON COMMIT
* action we need to take.
*/
if (action == ONCOMMIT_NOOP || action == ONCOMMIT_PRESERVE_ROWS)
return;
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
oc = (OnCommitItem *) palloc(sizeof(OnCommitItem));
oc->relid = relid;
oc->oncommit = action;
oc->creating_subid = GetCurrentSubTransactionId();
oc->deleting_subid = InvalidSubTransactionId;
on_commits = lcons(oc, on_commits);
MemoryContextSwitchTo(oldcxt);
}
/*
* Unregister any ON COMMIT action when a relation is deleted.
*
* Actually, we only mark the OnCommitItem entry as to be deleted after commit.
*/void
remove_on_commit_action(Oid relid)
{
ListCell *l;
foreach(l, on_commits)
{
OnCommitItem *oc = (OnCommitItem *) lfirst(l);
if (oc->relid == relid)
{
oc->deleting_subid = GetCurrentSubTransactionId();
break;
}
}
}
/*
* Perform ON COMMIT actions.
*
* This is invoked just before actually committing, since it's possible
* to encounter errors.
*/
void
PreCommit_on_commit_actions(void)
{
ListCell *l;
List *oids_to_truncate = NIL;
foreach(l, on_commits)
{
OnCommitItem *oc = (OnCommitItem *) lfirst(l);
/* Ignore entry if already dropped in this xact */
if (oc->deleting_subid != InvalidSubTransactionId)
continue;
switch (oc->oncommit)
{
case ONCOMMIT_NOOP:
case ONCOMMIT_PRESERVE_ROWS:
/* Do nothing (there shouldn't be such entries, actually) */
break;
case ONCOMMIT_DELETE_ROWS:
oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
break;
case ONCOMMIT_DROP:
{
ObjectAddress object;
object.classId = RelationRelationId;
object.objectId = oc->relid;
object.objectSubId = 0;
performDeletion(&object, DROP_CASCADE);
/*
* Note that table deletion will call
* remove_on_commit_action, so the entry should get marked
* as deleted.
*/
Assert(oc->deleting_subid != InvalidSubTransactionId);
break;
}
}
}
if (oids_to_truncate != NIL)
{
heap_truncate(oids_to_truncate);
CommandCounterIncrement(); /* XXX needed? */
}}
/*
* Post-commit or post-abort cleanup for ON COMMIT management.
*
* All we do here is remove no-longer-needed OnCommitItem entries.
*
* During commit, remove entries that were deleted during this transaction;
* during abort, remove those created during this transaction.
*/
void
AtEOXact_on_commit_actions(bool isCommit)
{
ListCell *cur_item;
ListCell *prev_item;
prev_item = NULL;
cur_item = list_head(on_commits);
while (cur_item != NULL)
{
OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
if (isCommit ? oc->deleting_subid != InvalidSubTransactionId :
oc->creating_subid != InvalidSubTransactionId)
{
/* cur_item must be removed */
on_commits = list_delete_cell(on_commits, cur_item, prev_item);
pfree(oc);
if (prev_item)
cur_item = lnext(prev_item);
else
cur_item = list_head(on_commits);
}
else
{
/* cur_item must be preserved */
oc->creating_subid = InvalidSubTransactionId;
oc->deleting_subid = InvalidSubTransactionId;
prev_item = cur_item;
cur_item = lnext(prev_item);
}
}
}
/*
* Post-subcommit or post-subabort cleanup for ON COMMIT management.
*
* During subabort, we can immediately remove entries created during this
* subtransaction. During subcommit, just relabel entries marked during
* this subtransaction as being the parent's responsibility.
*/
void
AtEOSubXact_on_commit_actions(bool isCommit, SubTransactionId mySubid,
SubTransactionId parentSubid)
{
ListCell *cur_item;
ListCell *prev_item;
prev_item = NULL;
cur_item = list_head(on_commits);
while (cur_item != NULL)
{
OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
if (!isCommit && oc->creating_subid == mySubid)
{
/* cur_item must be removed */
on_commits = list_delete_cell(on_commits, cur_item, prev_item); pfree(oc);
if (prev_item)
cur_item = lnext(prev_item);
else
cur_item = list_head(on_commits);
}
else
{
/* cur_item must be preserved */
if (oc->creating_subid == mySubid)
oc->creating_subid = parentSubid;
if (oc->deleting_subid == mySubid)
oc->deleting_subid = isCommit ? parentSubid : InvalidSubTransactionId;
prev_item = cur_item;
cur_item = lnext(prev_item);
}
}
}