heap.c 56.95 KiB
/*-------------------------------------------------------------------------
*
* heap.c
* code to create and destroy POSTGRES heap relations
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.268 2004/06/06 04:52:55 tgl Exp $
*
*
* INTERFACE ROUTINES
* heap_create() - Create an uncataloged heap relation
* heap_create_with_catalog() - Create a cataloged relation
* heap_drop_with_catalog() - Removes named relation from catalogs
*
* NOTES
* this code taken from access/heap/create.c, which contains
* the old heap_create_with_catalog, amcreate, and amdestroy.
* those routines will soon call these routines using the function
* manager,
* just like the poorly named "NewXXX" routines do. The
* "New" routines are all going to die soon, once and for all!
* -cim 1/13/91
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "access/genam.h"
#include "catalog/catalog.h"
#include "catalog/catname.h"
#include "catalog/dependency.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/indexing.h"
#include "catalog/pg_attrdef.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_statistic.h"
#include "catalog/pg_type.h"
#include "commands/tablecmds.h"
#include "commands/trigger.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/planmain.h"
#include "optimizer/var.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "parser/parse_relation.h"
#include "rewrite/rewriteRemove.h"
#include "storage/smgr.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/relcache.h"
#include "utils/syscache.h"
static void AddNewRelationTuple(Relation pg_class_desc,
Relation new_rel_desc,
Oid new_rel_oid, Oid new_type_oid,
char relkind);
static void AddNewRelationType(const char *typeName,
Oid typeNamespace, Oid new_rel_oid,
char new_rel_kind,
Oid new_type_oid);
static void RelationRemoveInheritance(Relation relation);
static void StoreRelCheck(Relation rel, char *ccname, char *ccbin);
static void StoreConstraints(Relation rel, TupleDesc tupdesc);
static void SetRelationNumChecks(Relation rel, int numchecks);
/* ----------------------------------------------------------------
* XXX UGLY HARD CODED BADNESS FOLLOWS XXX
*
* these should all be moved to someplace in the lib/catalog
* module, if not obliterated first.
* ----------------------------------------------------------------
*/
/*
* Note:
* Should the system special case these attributes in the future?
* Advantage: consume much less space in the ATTRIBUTE relation.
* Disadvantage: special cases will be all over the place.
*/
static FormData_pg_attribute a1 = {
0, {"ctid"}, TIDOID, 0, sizeof(ItemPointerData),
SelfItemPointerAttributeNumber, 0, -1, -1,
false, 'p', 's', true, false, false, true, 0
};
static FormData_pg_attribute a2 = {
0, {"oid"}, OIDOID, 0, sizeof(Oid),
ObjectIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
static FormData_pg_attribute a3 = {
0, {"xmin"}, XIDOID, 0, sizeof(TransactionId),
MinTransactionIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
static FormData_pg_attribute a4 = {
0, {"cmin"}, CIDOID, 0, sizeof(CommandId),
MinCommandIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
static FormData_pg_attribute a5 = {
0, {"xmax"}, XIDOID, 0, sizeof(TransactionId),
MaxTransactionIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
static FormData_pg_attribute a6 = {
0, {"cmax"}, CIDOID, 0, sizeof(CommandId),
MaxCommandIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
/*
* We decided to call this attribute "tableoid" rather than say
* "classoid" on the basis that in the future there may be more than one
* table of a particular class/type. In any case table is still the word
* used in SQL.
*/
static FormData_pg_attribute a7 = {
0, {"tableoid"}, OIDOID, 0, sizeof(Oid),
TableOidAttributeNumber, 0, -1, -1, true, 'p', 'i', true, false, false, true, 0
};
static Form_pg_attribute SysAtt[] = {&a1, &a2, &a3, &a4, &a5, &a6, &a7};
/*
* This function returns a Form_pg_attribute pointer for a system attribute.
* Note that we elog if the presented attno is invalid, which would only
* happen if there's a problem upstream.
*/
Form_pg_attribute
SystemAttributeDefinition(AttrNumber attno, bool relhasoids)
{
if (attno >= 0 || attno < -(int) lengthof(SysAtt))
elog(ERROR, "invalid system attribute number %d", attno);
if (attno == ObjectIdAttributeNumber && !relhasoids)
elog(ERROR, "invalid system attribute number %d", attno);
return SysAtt[-attno - 1];
}
/*
* If the given name is a system attribute name, return a Form_pg_attribute
* pointer for a prototype definition. If not, return NULL.
*/
Form_pg_attribute
SystemAttributeByName(const char *attname, bool relhasoids)
{
int j;
for (j = 0; j < (int) lengthof(SysAtt); j++)
{
Form_pg_attribute att = SysAtt[j];
if (relhasoids || att->attnum != ObjectIdAttributeNumber)
{
if (strcmp(NameStr(att->attname), attname) == 0)
return att;
}
}
return NULL;
}
/* ----------------------------------------------------------------
* XXX END OF UGLY HARD CODED BADNESS XXX
* ---------------------------------------------------------------- */
/* ----------------------------------------------------------------
* heap_create - Create an uncataloged heap relation
*
* rel->rd_rel is initialized by RelationBuildLocalRelation,
* and is mostly zeroes at return.
*
* Remove the system relation specific code to elsewhere eventually.
*
* If storage_create is TRUE then heap_storage_create is called here,
* else caller must call heap_storage_create later (or not at all,
* if the relation doesn't need physical storage).
* ----------------------------------------------------------------
*/
Relation
heap_create(const char *relname,
Oid relnamespace,
TupleDesc tupDesc,
bool shared_relation,
bool storage_create,
bool allow_system_table_mods)
{ Oid relid;
Oid dbid = shared_relation ? InvalidOid : MyDatabaseId;
bool nailme = false;
RelFileNode rnode;
Relation rel;
/*
* sanity checks
*/
if (!allow_system_table_mods &&
(IsSystemNamespace(relnamespace) || IsToastNamespace(relnamespace)) &&
IsNormalProcessingMode())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to create \"%s.%s\"",
get_namespace_name(relnamespace), relname),
errdetail("System catalog modifications are currently disallowed.")));
/*
* Real ugly stuff to assign the proper relid in the relation
* descriptor follows. Note that only "bootstrapped" relations whose
* OIDs are hard-coded in pg_class.h should be listed here. We also
* have to recognize those rels that must be nailed in cache.
*/
if (IsSystemNamespace(relnamespace))
{
if (strcmp(TypeRelationName, relname) == 0)
{
nailme = true;
relid = RelOid_pg_type;
}
else if (strcmp(AttributeRelationName, relname) == 0)
{
nailme = true;
relid = RelOid_pg_attribute;
}
else if (strcmp(ProcedureRelationName, relname) == 0)
{
nailme = true;
relid = RelOid_pg_proc;
}
else if (strcmp(RelationRelationName, relname) == 0)
{
nailme = true;
relid = RelOid_pg_class;
}
else if (strcmp(ShadowRelationName, relname) == 0)
relid = RelOid_pg_shadow;
else if (strcmp(GroupRelationName, relname) == 0)
relid = RelOid_pg_group;
else if (strcmp(DatabaseRelationName, relname) == 0)
relid = RelOid_pg_database;
else
relid = newoid();
}
else
relid = newoid();
/*
* For now, the physical identifier of the relation is the same as the
* logical identifier.
*/
rnode.tblNode = dbid;
rnode.relNode = relid;
/*
* build the relcache entry.
*/
rel = RelationBuildLocalRelation(relname,
relnamespace, tupDesc,
relid, dbid,
rnode,
nailme);
/*
* have the storage manager create the relation's disk file, if
* wanted.
*/
if (storage_create)
heap_storage_create(rel);
return rel;
}
void
heap_storage_create(Relation rel)
{
Assert(rel->rd_smgr == NULL);
rel->rd_smgr = smgropen(rel->rd_node);
smgrcreate(rel->rd_smgr, rel->rd_istemp, false);
}
/* ----------------------------------------------------------------
* heap_create_with_catalog - Create a cataloged relation
*
* this is done in 6 steps:
*
* 1) CheckAttributeNamesTypes() is used to make certain the tuple
* descriptor contains a valid set of attribute names and types
*
* 2) pg_class is opened and get_relname_relid()
* performs a scan to ensure that no relation with the
* same name already exists.
*
* 3) heap_create() is called to create the new relation on disk.
*
* 4) AddNewRelationTuple() is called to register the
* relation in pg_class.
*
* 5) TypeCreate() is called to define a new type corresponding
* to the new relation.
*
* 6) AddNewAttributeTuples() is called to register the
* new relation's schema in pg_attribute.
*
* 7) StoreConstraints is called () - vadim 08/22/97
*
* 8) the relations are closed and the new relation's oid
* is returned.
*
* ----------------------------------------------------------------
*/
/* --------------------------------
* CheckAttributeNamesTypes
*
* this is used to make certain the tuple descriptor contains a
* valid set of attribute names and datatypes. a problem simply
* generates ereport(ERROR) which aborts the current transaction.
* --------------------------------
*/
void
CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind)
{
int i;
int j;
int natts = tupdesc->natts;
/* Sanity check on column count */ if (natts < 0 || natts > MaxHeapAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("tables can have at most %d columns",
MaxHeapAttributeNumber)));
/*
* first check for collision with system attribute names
*
* Skip this for a view or type relation, since those don't have system
* attributes.
*/
if (relkind != RELKIND_VIEW && relkind != RELKIND_COMPOSITE_TYPE)
{
for (i = 0; i < natts; i++)
{
if (SystemAttributeByName(NameStr(tupdesc->attrs[i]->attname),
tupdesc->tdhasoid) != NULL)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column name \"%s\" conflicts with a system column name",
NameStr(tupdesc->attrs[i]->attname))));
}
}
/*
* next check for repeated attribute names
*/
for (i = 1; i < natts; i++)
{
for (j = 0; j < i; j++)
{
if (strcmp(NameStr(tupdesc->attrs[j]->attname),
NameStr(tupdesc->attrs[i]->attname)) == 0)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column name \"%s\" is duplicated",
NameStr(tupdesc->attrs[j]->attname))));
}
}
/*
* next check the attribute types
*/
for (i = 0; i < natts; i++)
{
CheckAttributeType(NameStr(tupdesc->attrs[i]->attname),
tupdesc->attrs[i]->atttypid);
}
}
/* --------------------------------
* CheckAttributeType
*
* Verify that the proposed datatype of an attribute is legal.
* This is needed because there are types (and pseudo-types)
* in the catalogs that we do not support as elements of real tuples.
* --------------------------------
*/
void
CheckAttributeType(const char *attname, Oid atttypid)
{
char att_typtype = get_typtype(atttypid);
/*
* Warn user, but don't fail, if column to be created has UNKNOWN type
* (usually as a result of a 'retrieve into' - jolly)
*
* Refuse any attempt to create a pseudo-type column or one that uses a
* non-standalone composite type. (We could support using table rowtypes * as attributes, if we were willing to make ALTER TABLE hugely more
* complex, but for now let's limit the damage ...)
*/
if (atttypid == UNKNOWNOID)
ereport(WARNING,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column \"%s\" has type \"unknown\"", attname),
errdetail("Proceeding with relation creation anyway.")));
else if (att_typtype == 'p')
{
/* Special hack for pg_statistic: allow ANYARRAY during initdb */
if (atttypid != ANYARRAYOID || IsUnderPostmaster)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column \"%s\" has pseudo-type %s",
attname, format_type_be(atttypid))));
}
else if (att_typtype == 'c')
{
Oid typrelid = get_typ_typrelid(atttypid);
if (get_rel_relkind(typrelid) != RELKIND_COMPOSITE_TYPE)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column \"%s\" has composite type %s",
attname, format_type_be(atttypid))));
}
}
/* --------------------------------
* AddNewAttributeTuples
*
* this registers the new relation's schema by adding
* tuples to pg_attribute.
* --------------------------------
*/
static void
AddNewAttributeTuples(Oid new_rel_oid,
TupleDesc tupdesc,
char relkind,
bool oidislocal,
int oidinhcount)
{
Form_pg_attribute *dpp;
int i;
HeapTuple tup;
Relation rel;
CatalogIndexState indstate;
int natts = tupdesc->natts;
ObjectAddress myself,
referenced;
/*
* open pg_attribute and its indexes.
*/
rel = heap_openr(AttributeRelationName, RowExclusiveLock);
indstate = CatalogOpenIndexes(rel);
/*
* First we add the user attributes. This is also a convenient place
* to add dependencies on their datatypes.
*/
dpp = tupdesc->attrs;
for (i = 0; i < natts; i++)
{
/* Fill in the correct relation OID */
(*dpp)->attrelid = new_rel_oid;
/* Make sure these are OK, too */
(*dpp)->attstattarget = -1; (*dpp)->attcacheoff = -1;
tup = heap_addheader(Natts_pg_attribute,
false,
ATTRIBUTE_TUPLE_SIZE,
(void *) *dpp);
simple_heap_insert(rel, tup);
CatalogIndexInsert(indstate, tup);
heap_freetuple(tup);
myself.classId = RelOid_pg_class;
myself.objectId = new_rel_oid;
myself.objectSubId = i + 1;
referenced.classId = RelOid_pg_type;
referenced.objectId = (*dpp)->atttypid;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
dpp++;
}
/*
* Next we add the system attributes. Skip OID if rel has no OIDs.
* Skip all for a view or type relation. We don't bother with making
* datatype dependencies here, since presumably all these types are
* pinned.
*/
if (relkind != RELKIND_VIEW && relkind != RELKIND_COMPOSITE_TYPE)
{
dpp = SysAtt;
for (i = 0; i < -1 - FirstLowInvalidHeapAttributeNumber; i++)
{
if (tupdesc->tdhasoid ||
(*dpp)->attnum != ObjectIdAttributeNumber)
{
Form_pg_attribute attStruct;
tup = heap_addheader(Natts_pg_attribute,
false,
ATTRIBUTE_TUPLE_SIZE,
(void *) *dpp);
attStruct = (Form_pg_attribute) GETSTRUCT(tup);
/* Fill in the correct relation OID in the copied tuple */
attStruct->attrelid = new_rel_oid;
/* Fill in correct inheritance info for the OID column */
if (attStruct->attnum == ObjectIdAttributeNumber)
{
attStruct->attislocal = oidislocal;
attStruct->attinhcount = oidinhcount;
}
/*
* Unneeded since they should be OK in the constant data
* anyway
*/
/* attStruct->attstattarget = 0; */
/* attStruct->attcacheoff = -1; */
simple_heap_insert(rel, tup);
CatalogIndexInsert(indstate, tup);
heap_freetuple(tup);
}
dpp++; }
}
/*
* clean up
*/
CatalogCloseIndexes(indstate);
heap_close(rel, RowExclusiveLock);
}
/* --------------------------------
* AddNewRelationTuple
*
* this registers the new relation in the catalogs by
* adding a tuple to pg_class.
* --------------------------------
*/
static void
AddNewRelationTuple(Relation pg_class_desc,
Relation new_rel_desc,
Oid new_rel_oid,
Oid new_type_oid,
char relkind)
{
Form_pg_class new_rel_reltup;
HeapTuple tup;
/*
* first we update some of the information in our uncataloged
* relation's relation descriptor.
*/
new_rel_reltup = new_rel_desc->rd_rel;
/*
* Here we insert bogus estimates of the size of the new relation. In
* reality, of course, the new relation has 0 tuples and pages, and if
* we were tracking these statistics accurately then we'd set the
* fields that way. But at present the stats will be updated only by
* VACUUM or CREATE INDEX, and the user might insert a lot of tuples
* before he gets around to doing either of those. So, instead of
* saying the relation is empty, we insert guesstimates. The point is
* to keep the optimizer from making really stupid choices on
* never-yet-vacuumed tables; so the estimates need only be large
* enough to discourage the optimizer from using nested-loop plans.
* With this hack, nested-loop plans will be preferred only after the
* table has been proven to be small by VACUUM or CREATE INDEX.
* Maintaining the stats on-the-fly would solve the problem more
* cleanly, but the overhead of that would likely cost more than it'd
* save. (NOTE: CREATE INDEX inserts the same bogus estimates if it
* finds the relation has 0 rows and pages. See index.c.)
*/
switch (relkind)
{
case RELKIND_RELATION:
case RELKIND_INDEX:
case RELKIND_TOASTVALUE:
new_rel_reltup->relpages = 10; /* bogus estimates */
new_rel_reltup->reltuples = 1000;
break;
case RELKIND_SEQUENCE:
new_rel_reltup->relpages = 1;
new_rel_reltup->reltuples = 1;
break;
default: /* views, etc */
new_rel_reltup->relpages = 0;
new_rel_reltup->reltuples = 0;
break;
}
new_rel_reltup->relowner = GetUserId();
new_rel_reltup->reltype = new_type_oid;
new_rel_reltup->relkind = relkind;
new_rel_desc->rd_att->tdtypeid = new_type_oid;
/* ----------------
* now form a tuple to add to pg_class
* XXX Natts_pg_class_fixed is a hack - see pg_class.h
* ----------------
*/
tup = heap_addheader(Natts_pg_class_fixed,
true,
CLASS_TUPLE_SIZE,
(void *) new_rel_reltup);
/* force tuple to have the desired OID */
HeapTupleSetOid(tup, new_rel_oid);
/*
* finally insert the new tuple, update the indexes, and clean up.
*/
simple_heap_insert(pg_class_desc, tup);
CatalogUpdateIndexes(pg_class_desc, tup);
heap_freetuple(tup);
}
/* --------------------------------
* AddNewRelationType -
*
* define a composite type corresponding to the new relation
* --------------------------------
*/
static void
AddNewRelationType(const char *typeName,
Oid typeNamespace,
Oid new_rel_oid,
char new_rel_kind,
Oid new_type_oid)
{
TypeCreate(typeName, /* type name */
typeNamespace, /* type namespace */
new_type_oid, /* preassigned oid for type */
new_rel_oid, /* relation oid */
new_rel_kind, /* relation kind */
-1, /* internal size (varlena) */
'c', /* type-type (complex) */
',', /* default array delimiter */
F_RECORD_IN, /* input procedure */
F_RECORD_OUT, /* output procedure */
F_RECORD_RECV, /* receive procedure */
F_RECORD_SEND, /* send procedure */
InvalidOid, /* analyze procedure - default */
InvalidOid, /* array element type - irrelevant */
InvalidOid, /* domain base type - irrelevant */
NULL, /* default type value - none */
NULL, /* default type binary representation */
false, /* passed by reference */
'd', /* alignment - must be the largest! */
'x', /* fully TOASTable */
-1, /* typmod */
0, /* array dimensions for typBaseType */
false); /* Type NOT NULL */
}
/* --------------------------------
* heap_create_with_catalog *
* creates a new cataloged relation. see comments above.
* --------------------------------
*/
Oid
heap_create_with_catalog(const char *relname,
Oid relnamespace,
TupleDesc tupdesc,
char relkind,
bool shared_relation,
bool oidislocal,
int oidinhcount,
OnCommitAction oncommit,
bool allow_system_table_mods)
{
Relation pg_class_desc;
Relation new_rel_desc;
Oid new_rel_oid;
Oid new_type_oid;
/*
* sanity checks
*/
Assert(IsNormalProcessingMode() || IsBootstrapProcessingMode());
CheckAttributeNamesTypes(tupdesc, relkind);
if (get_relname_relid(relname, relnamespace))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" already exists", relname)));
/*
* Create the relcache entry (mostly dummy at this point) and the
* physical disk file. (If we fail further down, it's the smgr's
* responsibility to remove the disk file again.)
*
* NB: create a physical file only if it's not a view or type relation.
*/
new_rel_desc = heap_create(relname,
relnamespace,
tupdesc,
shared_relation,
(relkind != RELKIND_VIEW &&
relkind != RELKIND_COMPOSITE_TYPE),
allow_system_table_mods);
/* Fetch the relation OID assigned by heap_create */
new_rel_oid = RelationGetRelid(new_rel_desc);
/* Assign an OID for the relation's tuple type */
new_type_oid = newoid();
/*
* now create an entry in pg_class for the relation.
*
* NOTE: we could get a unique-index failure here, in case someone else
* is creating the same relation name in parallel but hadn't committed
* yet when we checked for a duplicate name above.
*/
pg_class_desc = heap_openr(RelationRelationName, RowExclusiveLock);
AddNewRelationTuple(pg_class_desc,
new_rel_desc,
new_rel_oid,
new_type_oid,
relkind);
/*
* since defining a relation also defines a complex type, we add a new * system type corresponding to the new relation.
*
* NOTE: we could get a unique-index failure here, in case the same name
* has already been used for a type.
*/
AddNewRelationType(relname,
relnamespace,
new_rel_oid,
relkind,
new_type_oid);
/*
* now add tuples to pg_attribute for the attributes in our new
* relation.
*/
AddNewAttributeTuples(new_rel_oid, new_rel_desc->rd_att, relkind,
oidislocal, oidinhcount);
/*
* make a dependency link to force the relation to be deleted if its
* namespace is. Skip this in bootstrap mode, since we don't make
* dependencies while bootstrapping.
*/
if (!IsBootstrapProcessingMode())
{
ObjectAddress myself,
referenced;
myself.classId = RelOid_pg_class;
myself.objectId = new_rel_oid;
myself.objectSubId = 0;
referenced.classId = get_system_catalog_relid(NamespaceRelationName);
referenced.objectId = relnamespace;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
}
/*
* store constraints and defaults passed in the tupdesc, if any.
*
* NB: this may do a CommandCounterIncrement and rebuild the relcache
* entry, so the relation must be valid and self-consistent at this
* point. In particular, there are not yet constraints and defaults
* anywhere.
*/
StoreConstraints(new_rel_desc, tupdesc);
/*
* If there's a special on-commit action, remember it
*/
if (oncommit != ONCOMMIT_NOOP)
register_on_commit_action(new_rel_oid, oncommit);
/*
* ok, the relation has been cataloged, so close our relations and
* return the oid of the newly created relation.
*/
heap_close(new_rel_desc, NoLock); /* do not unlock till end of xact */
heap_close(pg_class_desc, RowExclusiveLock);
return new_rel_oid;
}
/*
* RelationRemoveInheritance
*
* Formerly, this routine checked for child relations and aborted the
* deletion if any were found. Now we rely on the dependency mechanism
* to check for or delete child relations. By the time we get here, * there are no children and we need only remove any pg_inherits rows
* linking this relation to its parent(s).
*/
static void
RelationRemoveInheritance(Relation relation)
{
Relation catalogRelation;
SysScanDesc scan;
ScanKeyData key;
HeapTuple tuple;
catalogRelation = heap_openr(InheritsRelationName, RowExclusiveLock);
ScanKeyInit(&key,
Anum_pg_inherits_inhrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndex, true,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
simple_heap_delete(catalogRelation, &tuple->t_self);
systable_endscan(scan);
heap_close(catalogRelation, RowExclusiveLock);
}
/*
* DeleteRelationTuple
*
* Remove pg_class row for the given relid.
*
* Note: this is shared by relation deletion and index deletion. It's
* not intended for use anyplace else.
*/
void
DeleteRelationTuple(Oid relid)
{
Relation pg_class_desc;
HeapTuple tup;
/* Grab an appropriate lock on the pg_class relation */
pg_class_desc = heap_openr(RelationRelationName, RowExclusiveLock);
tup = SearchSysCache(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for relation %u", relid);
/* delete the relation tuple from pg_class, and finish up */
simple_heap_delete(pg_class_desc, &tup->t_self);
ReleaseSysCache(tup);
heap_close(pg_class_desc, RowExclusiveLock);
}
/*
* DeleteAttributeTuples
*
* Remove pg_attribute rows for the given relid.
*
* Note: this is shared by relation deletion and index deletion. It's
* not intended for use anyplace else.
*/
void
DeleteAttributeTuples(Oid relid)
{ Relation attrel;
SysScanDesc scan;
ScanKeyData key[1];
HeapTuple atttup;
/* Grab an appropriate lock on the pg_attribute relation */
attrel = heap_openr(AttributeRelationName, RowExclusiveLock);
/* Use the index to scan only attributes of the target relation */
ScanKeyInit(&key[0],
Anum_pg_attribute_attrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
scan = systable_beginscan(attrel, AttributeRelidNumIndex, true,
SnapshotNow, 1, key);
/* Delete all the matching tuples */
while ((atttup = systable_getnext(scan)) != NULL)
simple_heap_delete(attrel, &atttup->t_self);
/* Clean up after the scan */
systable_endscan(scan);
heap_close(attrel, RowExclusiveLock);
}
/*
* RemoveAttributeById
*
* This is the guts of ALTER TABLE DROP COLUMN: actually mark the attribute
* deleted in pg_attribute. We also remove pg_statistic entries for it.
* (Everything else needed, such as getting rid of any pg_attrdef entry,
* is handled by dependency.c.)
*/
void
RemoveAttributeById(Oid relid, AttrNumber attnum)
{
Relation rel;
Relation attr_rel;
HeapTuple tuple;
Form_pg_attribute attStruct;
char newattname[NAMEDATALEN];
/*
* Grab an exclusive lock on the target table, which we will NOT
* release until end of transaction. (In the simple case where we are
* directly dropping this column, AlterTableDropColumn already did
* this ... but when cascading from a drop of some other object, we
* may not have any lock.)
*/
rel = relation_open(relid, AccessExclusiveLock);
attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);
tuple = SearchSysCacheCopy(ATTNUM,
ObjectIdGetDatum(relid),
Int16GetDatum(attnum),
0, 0);
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
attnum, relid);
attStruct = (Form_pg_attribute) GETSTRUCT(tuple);
if (attnum < 0)
{
/* System attribute (probably OID) ... just delete the row */
simple_heap_delete(attr_rel, &tuple->t_self);
}
else {
/* Dropping user attributes is lots harder */
/* Mark the attribute as dropped */
attStruct->attisdropped = true;
/*
* Set the type OID to invalid. A dropped attribute's type link
* cannot be relied on (once the attribute is dropped, the type might
* be too). Fortunately we do not need the type row --- the only
* really essential information is the type's typlen and typalign,
* which are preserved in the attribute's attlen and attalign. We set
* atttypid to zero here as a means of catching code that incorrectly
* expects it to be valid.
*/
attStruct->atttypid = InvalidOid;
/* Remove any NOT NULL constraint the column may have */
attStruct->attnotnull = false;
/* We don't want to keep stats for it anymore */
attStruct->attstattarget = 0;
/* Change the column name to something that isn't likely to conflict */
snprintf(newattname, sizeof(newattname),
"........pg.dropped.%d........", attnum);
namestrcpy(&(attStruct->attname), newattname);
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
}
/*
* Because updating the pg_attribute row will trigger a relcache flush
* for the target relation, we need not do anything else to notify
* other backends of the change.
*/
heap_close(attr_rel, RowExclusiveLock);
if (attnum > 0)
RemoveStatistics(rel, attnum);
relation_close(rel, NoLock);
}
/*
* RemoveAttrDefault
*
* If the specified relation/attribute has a default, remove it.
* (If no default, raise error if complain is true, else return quietly.)
*/
void
RemoveAttrDefault(Oid relid, AttrNumber attnum,
DropBehavior behavior, bool complain)
{
Relation attrdef_rel;
ScanKeyData scankeys[2];
SysScanDesc scan;
HeapTuple tuple;
bool found = false;
attrdef_rel = heap_openr(AttrDefaultRelationName, RowExclusiveLock);
ScanKeyInit(&scankeys[0],
Anum_pg_attrdef_adrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid)); ScanKeyInit(&scankeys[1],
Anum_pg_attrdef_adnum,
BTEqualStrategyNumber, F_INT2EQ,
Int16GetDatum(attnum));
scan = systable_beginscan(attrdef_rel, AttrDefaultIndex, true,
SnapshotNow, 2, scankeys);
/* There should be at most one matching tuple, but we loop anyway */
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
{
ObjectAddress object;
object.classId = RelationGetRelid(attrdef_rel);
object.objectId = HeapTupleGetOid(tuple);
object.objectSubId = 0;
performDeletion(&object, behavior);
found = true;
}
systable_endscan(scan);
heap_close(attrdef_rel, RowExclusiveLock);
if (complain && !found)
elog(ERROR, "could not find attrdef tuple for relation %u attnum %d",
relid, attnum);
}
/*
* RemoveAttrDefaultById
*
* Remove a pg_attrdef entry specified by OID. This is the guts of
* attribute-default removal. Note it should be called via performDeletion,
* not directly.
*/
void
RemoveAttrDefaultById(Oid attrdefId)
{
Relation attrdef_rel;
Relation attr_rel;
Relation myrel;
ScanKeyData scankeys[1];
SysScanDesc scan;
HeapTuple tuple;
Oid myrelid;
AttrNumber myattnum;
/* Grab an appropriate lock on the pg_attrdef relation */
attrdef_rel = heap_openr(AttrDefaultRelationName, RowExclusiveLock);
/* Find the pg_attrdef tuple */
ScanKeyInit(&scankeys[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(attrdefId));
scan = systable_beginscan(attrdef_rel, AttrDefaultOidIndex, true,
SnapshotNow, 1, scankeys);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for attrdef %u", attrdefId);
myrelid = ((Form_pg_attrdef) GETSTRUCT(tuple))->adrelid;
myattnum = ((Form_pg_attrdef) GETSTRUCT(tuple))->adnum;
/* Get an exclusive lock on the relation owning the attribute */
myrel = relation_open(myrelid, AccessExclusiveLock);
/* Now we can delete the pg_attrdef row */
simple_heap_delete(attrdef_rel, &tuple->t_self);
systable_endscan(scan);
heap_close(attrdef_rel, RowExclusiveLock);
/* Fix the pg_attribute row */
attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);
tuple = SearchSysCacheCopy(ATTNUM,
ObjectIdGetDatum(myrelid),
Int16GetDatum(myattnum),
0, 0);
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
myattnum, myrelid);
((Form_pg_attribute) GETSTRUCT(tuple))->atthasdef = false;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
/*
* Our update of the pg_attribute row will force a relcache rebuild,
* so there's nothing else to do here.
*/
heap_close(attr_rel, RowExclusiveLock);
/* Keep lock on attribute's rel until end of xact */
relation_close(myrel, NoLock);
}
/* ----------------------------------------------------------------
* heap_drop_with_catalog - removes specified relation from catalogs
*
* 1) open relation, acquire exclusive lock.
* 2) flush relation buffers from bufmgr
* 3) remove inheritance information
* 4) remove pg_statistic tuples
* 5) remove pg_attribute tuples
* 6) remove pg_class tuple
* 7) unlink relation file
*
* Note that this routine is not responsible for dropping objects that are
* linked to the pg_class entry via dependencies (for example, indexes and
* constraints). Those are deleted by the dependency-tracing logic in
* dependency.c before control gets here. In general, therefore, this routine
* should never be called directly; go through performDeletion() instead.
* ----------------------------------------------------------------
*/
void
heap_drop_with_catalog(Oid rid)
{
Relation rel;
/*
* Open and lock the relation.
*/
rel = relation_open(rid, AccessExclusiveLock);
/*
* Release all buffers that belong to this relation, after writing any
* that are dirty
*/
FlushRelationBuffers(rel, (BlockNumber) 0);
/* * remove inheritance information
*/
RelationRemoveInheritance(rel);
/*
* delete statistics
*/
RemoveStatistics(rel, 0);
/*
* delete attribute tuples
*/
DeleteAttributeTuples(RelationGetRelid(rel));
/*
* delete relation tuple
*/
DeleteRelationTuple(RelationGetRelid(rel));
/*
* forget any ON COMMIT action for the rel
*/
remove_on_commit_action(rid);
/*
* unlink the relation's physical file and finish up.
*/
if (rel->rd_rel->relkind != RELKIND_VIEW &&
rel->rd_rel->relkind != RELKIND_COMPOSITE_TYPE)
{
if (rel->rd_smgr == NULL)
rel->rd_smgr = smgropen(rel->rd_node);
smgrscheduleunlink(rel->rd_smgr, rel->rd_istemp);
rel->rd_smgr = NULL;
}
/*
* Close relcache entry, but *keep* AccessExclusiveLock on the
* relation until transaction commit. This ensures no one else will
* try to do something with the doomed relation.
*/
relation_close(rel, NoLock);
/*
* flush the relation from the relcache
*/
RelationForgetRelation(rid);
}
/*
* Store a default expression for column attnum of relation rel.
* The expression must be presented as a nodeToString() string.
*/
void
StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin)
{
Node *expr;
char *adsrc;
Relation adrel;
HeapTuple tuple;
Datum values[4];
static char nulls[4] = {' ', ' ', ' ', ' '};
Relation attrrel;
HeapTuple atttup;
Form_pg_attribute attStruct;
Oid attrdefOid;
ObjectAddress colobject,
defobject;
/*
* Need to construct source equivalent of given node-string.
*/
expr = stringToNode(adbin);
/*
* deparse it
*/
adsrc = deparse_expression(expr,
deparse_context_for(RelationGetRelationName(rel),
RelationGetRelid(rel)),
false, false);
/*
* Make the pg_attrdef entry.
*/
values[Anum_pg_attrdef_adrelid - 1] = RelationGetRelid(rel);
values[Anum_pg_attrdef_adnum - 1] = attnum;
values[Anum_pg_attrdef_adbin - 1] = DirectFunctionCall1(textin,
CStringGetDatum(adbin));
values[Anum_pg_attrdef_adsrc - 1] = DirectFunctionCall1(textin,
CStringGetDatum(adsrc));
adrel = heap_openr(AttrDefaultRelationName, RowExclusiveLock);
tuple = heap_formtuple(adrel->rd_att, values, nulls);
attrdefOid = simple_heap_insert(adrel, tuple);
CatalogUpdateIndexes(adrel, tuple);
defobject.classId = RelationGetRelid(adrel);
defobject.objectId = attrdefOid;
defobject.objectSubId = 0;
heap_close(adrel, RowExclusiveLock);
/* now can free some of the stuff allocated above */
pfree(DatumGetPointer(values[Anum_pg_attrdef_adbin - 1]));
pfree(DatumGetPointer(values[Anum_pg_attrdef_adsrc - 1]));
heap_freetuple(tuple);
pfree(adsrc);
/*
* Update the pg_attribute entry for the column to show that a default
* exists.
*/
attrrel = heap_openr(AttributeRelationName, RowExclusiveLock);
atttup = SearchSysCacheCopy(ATTNUM,
ObjectIdGetDatum(RelationGetRelid(rel)),
Int16GetDatum(attnum),
0, 0);
if (!HeapTupleIsValid(atttup))
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
attnum, RelationGetRelid(rel));
attStruct = (Form_pg_attribute) GETSTRUCT(atttup);
if (!attStruct->atthasdef)
{
attStruct->atthasdef = true;
simple_heap_update(attrrel, &atttup->t_self, atttup);
/* keep catalog indexes current */
CatalogUpdateIndexes(attrrel, atttup);
}
heap_close(attrrel, RowExclusiveLock);
heap_freetuple(atttup);
/*
* Make a dependency so that the pg_attrdef entry goes away if the
* column (or whole table) is deleted.
*/
colobject.classId = RelOid_pg_class; colobject.objectId = RelationGetRelid(rel);
colobject.objectSubId = attnum;
recordDependencyOn(&defobject, &colobject, DEPENDENCY_AUTO);
/*
* Record dependencies on objects used in the expression, too.
*/
recordDependencyOnExpr(&defobject, expr, NIL, DEPENDENCY_NORMAL);
}
/*
* Store a check-constraint expression for the given relation.
* The expression must be presented as a nodeToString() string.
*
* Caller is responsible for updating the count of constraints
* in the pg_class entry for the relation.
*/
static void
StoreRelCheck(Relation rel, char *ccname, char *ccbin)
{
Node *expr;
char *ccsrc;
List *varList;
int keycount;
int16 *attNos;
/*
* Convert condition to an expression tree.
*/
expr = stringToNode(ccbin);
/*
* deparse it
*/
ccsrc = deparse_expression(expr,
deparse_context_for(RelationGetRelationName(rel),
RelationGetRelid(rel)),
false, false);
/*
* Find columns of rel that are used in ccbin
*
* NB: pull_var_clause is okay here only because we don't allow
* subselects in check constraints; it would fail to examine the
* contents of subselects.
*/
varList = pull_var_clause(expr, false);
keycount = list_length(varList);
if (keycount > 0)
{
ListCell *vl;
int i = 0;
attNos = (int16 *) palloc(keycount * sizeof(int16));
foreach(vl, varList)
{
Var *var = (Var *) lfirst(vl);
int j;
for (j = 0; j < i; j++)
if (attNos[j] == var->varattno)
break;
if (j == i)
attNos[i++] = var->varattno;
}
keycount = i;
}
else attNos = NULL;
/*
* Create the Check Constraint
*/
CreateConstraintEntry(ccname, /* Constraint Name */
RelationGetNamespace(rel), /* namespace */
CONSTRAINT_CHECK, /* Constraint Type */
false, /* Is Deferrable */
false, /* Is Deferred */
RelationGetRelid(rel), /* relation */
attNos, /* attrs in the constraint */
keycount, /* # attrs in the constraint */
InvalidOid, /* not a domain constraint */
InvalidOid, /* Foreign key fields */
NULL,
0,
' ',
' ',
' ',
InvalidOid, /* no associated index */
expr, /* Tree form check constraint */
ccbin, /* Binary form check constraint */
ccsrc); /* Source form check constraint */
pfree(ccsrc);
}
/*
* Store defaults and constraints passed in via the tuple constraint struct.
*
* NOTE: only pre-cooked expressions will be passed this way, which is to
* say expressions inherited from an existing relation. Newly parsed
* expressions can be added later, by direct calls to StoreAttrDefault
* and StoreRelCheck (see AddRelationRawConstraints()).
*/
static void
StoreConstraints(Relation rel, TupleDesc tupdesc)
{
TupleConstr *constr = tupdesc->constr;
int i;
if (!constr)
return; /* nothing to do */
/*
* Deparsing of constraint expressions will fail unless the
* just-created pg_attribute tuples for this relation are made
* visible. So, bump the command counter. CAUTION: this will cause a
* relcache entry rebuild.
*/
CommandCounterIncrement();
for (i = 0; i < constr->num_defval; i++)
StoreAttrDefault(rel, constr->defval[i].adnum,
constr->defval[i].adbin);
for (i = 0; i < constr->num_check; i++)
StoreRelCheck(rel, constr->check[i].ccname,
constr->check[i].ccbin);
if (constr->num_check > 0)
SetRelationNumChecks(rel, constr->num_check);
}
/*
* AddRelationRawConstraints
*
* Add raw (not-yet-transformed) column default expressions and/or constraint
* check expressions to an existing relation. This is defined to do both * for efficiency in DefineRelation, but of course you can do just one or
* the other by passing empty lists.
*
* rel: relation to be modified
* rawColDefaults: list of RawColumnDefault structures
* rawConstraints: list of Constraint nodes
*
* All entries in rawColDefaults will be processed. Entries in rawConstraints
* will be processed only if they are CONSTR_CHECK type and contain a "raw"
* expression.
*
* Returns a list of CookedConstraint nodes that shows the cooked form of
* the default and constraint expressions added to the relation.
*
* NB: caller should have opened rel with AccessExclusiveLock, and should
* hold that lock till end of transaction. Also, we assume the caller has
* done a CommandCounterIncrement if necessary to make the relation's catalog
* tuples visible.
*/
List *
AddRelationRawConstraints(Relation rel,
List *rawColDefaults,
List *rawConstraints)
{
List *cookedConstraints = NIL;
char *relname = RelationGetRelationName(rel);
TupleDesc tupleDesc;
TupleConstr *oldconstr;
int numoldchecks;
ConstrCheck *oldchecks;
ParseState *pstate;
RangeTblEntry *rte;
int numchecks;
int constr_name_ctr = 0;
ListCell *cell;
Node *expr;
CookedConstraint *cooked;
/*
* Get info about existing constraints.
*/
tupleDesc = RelationGetDescr(rel);
oldconstr = tupleDesc->constr;
if (oldconstr)
{
numoldchecks = oldconstr->num_check;
oldchecks = oldconstr->check;
}
else
{
numoldchecks = 0;
oldchecks = NULL;
}
/*
* Create a dummy ParseState and insert the target relation as its
* sole rangetable entry. We need a ParseState for transformExpr.
*/
pstate = make_parsestate(NULL);
rte = addRangeTableEntryForRelation(pstate,
RelationGetRelid(rel),
makeAlias(relname, NIL),
false,
true);
addRTEtoQuery(pstate, rte, true, true);
/*
* Process column default expressions.
*/
foreach(cell, rawColDefaults) {
RawColumnDefault *colDef = (RawColumnDefault *) lfirst(cell);
Form_pg_attribute atp = rel->rd_att->attrs[colDef->attnum - 1];
expr = cookDefault(pstate, colDef->raw_default,
atp->atttypid, atp->atttypmod,
NameStr(atp->attname));
StoreAttrDefault(rel, colDef->attnum, nodeToString(expr));
cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
cooked->contype = CONSTR_DEFAULT;
cooked->name = NULL;
cooked->attnum = colDef->attnum;
cooked->expr = expr;
cookedConstraints = lappend(cookedConstraints, cooked);
}
/*
* Process constraint expressions.
*/
numchecks = numoldchecks;
foreach(cell, rawConstraints)
{
Constraint *cdef = (Constraint *) lfirst(cell);
char *ccname;
if (cdef->contype != CONSTR_CHECK || cdef->raw_expr == NULL)
continue;
Assert(cdef->cooked_expr == NULL);
/* Check name uniqueness, or generate a new name */
if (cdef->name != NULL)
{
ListCell *cell2;
ccname = cdef->name;
/* Check against pre-existing constraints */
if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
RelationGetRelid(rel),
RelationGetNamespace(rel),
ccname))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("constraint \"%s\" for relation \"%s\" already exists",
ccname, RelationGetRelationName(rel))));
/* Check against other new constraints */
/* Needed because we don't do CommandCounterIncrement in loop */
foreach(cell2, rawConstraints)
{
Constraint *cdef2 = (Constraint *) lfirst(cell2);
if (cdef2 == cdef ||
cdef2->contype != CONSTR_CHECK ||
cdef2->raw_expr == NULL ||
cdef2->name == NULL)
continue;
if (strcmp(cdef2->name, ccname) == 0)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("check constraint \"%s\" already exists",
ccname)));
}
}
else
{
bool success;
do
{ ListCell *cell2;
/*
* Generate a name that does not conflict with
* pre-existing constraints, nor with any auto-generated
* names so far.
*/
ccname = GenerateConstraintName(CONSTRAINT_RELATION,
RelationGetRelid(rel),
RelationGetNamespace(rel),
&constr_name_ctr);
/*
* Check against other new constraints, in case the user
* has specified a name that looks like an auto-generated
* name.
*/
success = true;
foreach(cell2, rawConstraints)
{
Constraint *cdef2 = (Constraint *) lfirst(cell2);
if (cdef2 == cdef ||
cdef2->contype != CONSTR_CHECK ||
cdef2->raw_expr == NULL ||
cdef2->name == NULL)
continue;
if (strcmp(cdef2->name, ccname) == 0)
{
success = false;
break;
}
}
} while (!success);
}
/*
* Transform raw parsetree to executable expression.
*/
expr = transformExpr(pstate, cdef->raw_expr);
/*
* Make sure it yields a boolean result.
*/
expr = coerce_to_boolean(pstate, expr, "CHECK");
/*
* Make sure no outside relations are referred to.
*/
if (list_length(pstate->p_rtable) != 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("only table \"%s\" can be referenced in check constraint",
relname)));
/*
* No subplans or aggregates, either...
*/
if (pstate->p_hasSubLinks)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot use subquery in check constraint")));
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in check constraint")));
/*
* OK, store it.
*/ StoreRelCheck(rel, ccname, nodeToString(expr));
numchecks++;
cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
cooked->contype = CONSTR_CHECK;
cooked->name = ccname;
cooked->attnum = 0;
cooked->expr = expr;
cookedConstraints = lappend(cookedConstraints, cooked);
}
/*
* Update the count of constraints in the relation's pg_class tuple.
* We do this even if there was no change, in order to ensure that an
* SI update message is sent out for the pg_class tuple, which will
* force other backends to rebuild their relcache entries for the rel.
* (This is critical if we added defaults but not constraints.)
*/
SetRelationNumChecks(rel, numchecks);
return cookedConstraints;
}
/*
* Update the count of constraints in the relation's pg_class tuple.
*
* Caller had better hold exclusive lock on the relation.
*
* An important side effect is that a SI update message will be sent out for
* the pg_class tuple, which will force other backends to rebuild their
* relcache entries for the rel. Also, this backend will rebuild its
* own relcache entry at the next CommandCounterIncrement.
*/
static void
SetRelationNumChecks(Relation rel, int numchecks)
{
Relation relrel;
HeapTuple reltup;
Form_pg_class relStruct;
relrel = heap_openr(RelationRelationName, RowExclusiveLock);
reltup = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(RelationGetRelid(rel)),
0, 0, 0);
if (!HeapTupleIsValid(reltup))
elog(ERROR, "cache lookup failed for relation %u",
RelationGetRelid(rel));
relStruct = (Form_pg_class) GETSTRUCT(reltup);
if (relStruct->relchecks != numchecks)
{
relStruct->relchecks = numchecks;
simple_heap_update(relrel, &reltup->t_self, reltup);
/* keep catalog indexes current */
CatalogUpdateIndexes(relrel, reltup);
}
else
{
/* Skip the disk update, but force relcache inval anyway */
CacheInvalidateRelcache(rel);
}
heap_freetuple(reltup);
heap_close(relrel, RowExclusiveLock);
}
/* * Take a raw default and convert it to a cooked format ready for
* storage.
*
* Parse state should be set up to recognize any vars that might appear
* in the expression. (Even though we plan to reject vars, it's more
* user-friendly to give the correct error message than "unknown var".)
*
* If atttypid is not InvalidOid, coerce the expression to the specified
* type (and typmod atttypmod). attname is only needed in this case:
* it is used in the error message, if any.
*/
Node *
cookDefault(ParseState *pstate,
Node *raw_default,
Oid atttypid,
int32 atttypmod,
char *attname)
{
Node *expr;
Assert(raw_default != NULL);
/*
* Transform raw parsetree to executable expression.
*/
expr = transformExpr(pstate, raw_default);
/*
* Make sure default expr does not refer to any vars.
*/
if (contain_var_clause(expr))
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("cannot use column references in default expression")));
/*
* It can't return a set either.
*/
if (expression_returns_set(expr))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("default 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 default expression")));
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in default expression")));
/*
* Coerce the expression to the correct type and typmod, if given.
* This should match the parser's processing of non-defaulted
* expressions --- see updateTargetListEntry().
*/
if (OidIsValid(atttypid))
{
Oid type_id = exprType(expr);
expr = coerce_to_target_type(pstate, expr, type_id,
atttypid, atttypmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST);
if (expr == NULL)
ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" is of type %s"
" but default expression is of type %s",
attname,
format_type_be(atttypid),
format_type_be(type_id)),
errhint("You will need to rewrite or cast the expression.")));
}
return expr;
}
/*
* Removes all constraints on a relation that match the given name.
*
* It is the responsibility of the calling function to acquire a suitable
* lock on the relation.
*
* Returns: The number of constraints removed.
*/
int
RemoveRelConstraints(Relation rel, const char *constrName,
DropBehavior behavior)
{
int ndeleted = 0;
Relation conrel;
SysScanDesc conscan;
ScanKeyData key[1];
HeapTuple contup;
/* Grab an appropriate lock on the pg_constraint relation */
conrel = heap_openr(ConstraintRelationName, RowExclusiveLock);
/* Use the index to scan only constraints of the target relation */
ScanKeyInit(&key[0],
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
conscan = systable_beginscan(conrel, ConstraintRelidIndex, true,
SnapshotNow, 1, key);
/*
* Scan over the result set, removing any matching entries.
*/
while ((contup = systable_getnext(conscan)) != NULL)
{
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(contup);
if (strcmp(NameStr(con->conname), constrName) == 0)
{
ObjectAddress conobj;
conobj.classId = RelationGetRelid(conrel);
conobj.objectId = HeapTupleGetOid(contup);
conobj.objectSubId = 0;
performDeletion(&conobj, behavior);
ndeleted++;
}
}
/* Clean up after the scan */
systable_endscan(conscan);
heap_close(conrel, RowExclusiveLock);
return ndeleted;
}
/*
* RemoveStatistics --- remove entries in pg_statistic for a rel or column
*
* If attnum is zero, remove all entries for rel; else remove only the one
* for that column.
*/
void
RemoveStatistics(Relation rel, AttrNumber attnum)
{
Relation pgstatistic;
SysScanDesc scan;
ScanKeyData key[2];
int nkeys;
HeapTuple tuple;
pgstatistic = heap_openr(StatisticRelationName, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_statistic_starelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
if (attnum == 0)
nkeys = 1;
else
{
ScanKeyInit(&key[1],
Anum_pg_statistic_staattnum,
BTEqualStrategyNumber, F_INT2EQ,
Int16GetDatum(attnum));
nkeys = 2;
}
scan = systable_beginscan(pgstatistic, StatisticRelidAttnumIndex, true,
SnapshotNow, nkeys, key);
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
simple_heap_delete(pgstatistic, &tuple->t_self);
systable_endscan(scan);
heap_close(pgstatistic, RowExclusiveLock);
}
/*
* RelationTruncateIndexes - truncate all
* indexes associated with the heap relation to zero tuples.
*
* The routine will truncate and then reconstruct the indexes on
* the relation specified by the heapId parameter.
*/
static void
RelationTruncateIndexes(Oid heapId)
{
Relation heapRelation;
ListCell *indlist;
/*
* Open the heap rel. We need grab no lock because we assume
* heap_truncate is holding an exclusive lock on the heap rel.
*/
heapRelation = heap_open(heapId, NoLock);
/* Ask the relcache to produce a list of the indexes of the rel */
foreach(indlist, RelationGetIndexList(heapRelation))
{
Oid indexId = lfirst_oid(indlist); Relation currentIndex;
IndexInfo *indexInfo;
/* Open the index relation */
currentIndex = index_open(indexId);
/* Obtain exclusive lock on it, just to be sure */
LockRelation(currentIndex, AccessExclusiveLock);
/* Fetch info needed for index_build */
indexInfo = BuildIndexInfo(currentIndex);
/*
* Drop any buffers associated with this index. If they're dirty,
* they're just dropped without bothering to flush to disk.
*/
DropRelationBuffers(currentIndex);
/* Now truncate the actual data */
RelationTruncate(currentIndex, 0);
/* Initialize the index and rebuild */
index_build(heapRelation, currentIndex, indexInfo);
/*
* index_build will close both the heap and index relations (but
* not give up the locks we hold on them). We're done with this
* index, but we must re-open the heap rel.
*/
heapRelation = heap_open(heapId, NoLock);
}
/* Finish by closing the heap rel again */
heap_close(heapRelation, NoLock);
}
/*
* heap_truncate
*
* This routine deletes all data within the specified relation.
*
* This is not transaction-safe! There is another, transaction-safe
* implementation in commands/cluster.c. We now use this only for
* ON COMMIT truncation of temporary tables, where it doesn't matter.
*/
void
heap_truncate(Oid rid)
{
Relation rel;
Oid toastrelid;
/* Open relation for processing, and grab exclusive access on it. */
rel = heap_open(rid, AccessExclusiveLock);
/* Don't allow truncate on tables that are referenced by foreign keys */
heap_truncate_check_FKs(rel);
/*
* Release any buffers associated with this relation. If they're
* dirty, they're just dropped without bothering to flush to disk.
*/
DropRelationBuffers(rel);
/* Now truncate the actual data */
RelationTruncate(rel, 0);
/* If this relation has indexes, truncate the indexes too */
RelationTruncateIndexes(rid);
/* If it has a toast table, recursively truncate that too */ toastrelid = rel->rd_rel->reltoastrelid;
if (OidIsValid(toastrelid))
heap_truncate(toastrelid);
/*
* Close the relation, but keep exclusive lock on it until commit.
*/
heap_close(rel, NoLock);
}
/*
* heap_truncate_check_FKs
* Check for foreign keys referencing a relation that's to be truncated
*
* We disallow such FKs (except self-referential ones) since the whole point
* of TRUNCATE is to not scan the individual rows to be thrown away.
*
* This is split out so it can be shared by both implementations of truncate.
* Caller should already hold a suitable lock on the relation.
*/
void
heap_truncate_check_FKs(Relation rel)
{
Oid relid = RelationGetRelid(rel);
ScanKeyData key;
Relation fkeyRel;
SysScanDesc fkeyScan;
HeapTuple tuple;
/*
* Fast path: if the relation has no triggers, it surely has no FKs
* either.
*/
if (rel->rd_rel->reltriggers == 0)
return;
/*
* Otherwise, must scan pg_constraint. Right now, this is a seqscan
* because there is no available index on confrelid.
*/
fkeyRel = heap_openr(ConstraintRelationName, AccessShareLock);
ScanKeyInit(&key,
Anum_pg_constraint_confrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
fkeyScan = systable_beginscan(fkeyRel, NULL, false,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = systable_getnext(fkeyScan)))
{
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple);
if (con->contype == CONSTRAINT_FOREIGN && con->conrelid != relid)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot truncate a table referenced in a foreign key constraint"),
errdetail("Table \"%s\" references \"%s\" via foreign key constraint \"%s\".",
get_rel_name(con->conrelid),
RelationGetRelationName(rel),
NameStr(con->conname))));
}
systable_endscan(fkeyScan);
heap_close(fkeyRel, AccessShareLock);
}