-
Tom Lane authored
true at the very end of its processing, the update is broadcast via a shared-cache-inval message for the index; without this, existing backends that already have relcache entries for the index might never see it become valid. Also, force a relcache inval on the index's parent table at the same time, so that any cached plans for that table are re-planned; this ensures that the newly valid index will be used if appropriate. Aside from making C.I.C. behave more reasonably, this is necessary infrastructure for some aspects of the HOT patch. Pavan Deolasee, with a little further stuff from me.
Tom Lane authoredtrue at the very end of its processing, the update is broadcast via a shared-cache-inval message for the index; without this, existing backends that already have relcache entries for the index might never see it become valid. Also, force a relcache inval on the index's parent table at the same time, so that any cached plans for that table are re-planned; this ensures that the newly valid index will be used if appropriate. Aside from making C.I.C. behave more reasonably, this is necessary infrastructure for some aspects of the HOT patch. Pavan Deolasee, with a little further stuff from me.
relcache.c 112.59 KiB
/*-------------------------------------------------------------------------
*
* relcache.c
* POSTGRES relation descriptor cache code
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.260 2007/05/02 21:08:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* RelationCacheInitialize - initialize relcache (to empty)
* RelationCacheInitializePhase2 - finish initializing relcache
* RelationIdGetRelation - get a reldesc by relation id
* RelationClose - close an open relation
*
* NOTES
* The following code contains many undocumented hacks. Please be
* careful....
*/
#include "postgres.h"
#include <sys/file.h>
#include <fcntl.h>
#include <unistd.h>
#include "access/genam.h"
#include "access/heapam.h"
#include "access/reloptions.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_attrdef.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_rewrite.h"
#include "catalog/pg_type.h"
#include "commands/trigger.h"
#include "miscadmin.h"
#include "optimizer/clauses.h"
#include "optimizer/planmain.h"
#include "optimizer/prep.h"
#include "rewrite/rewriteDefine.h"
#include "storage/fd.h"
#include "storage/smgr.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/memutils.h"
#include "utils/relcache.h"
#include "utils/resowner.h"
#include "utils/syscache.h"
#include "utils/typcache.h"
/*
* name of relcache init file, used to speed up backend startup
*/
#define RELCACHE_INIT_FILENAME "pg_internal.init"
#define RELCACHE_INIT_FILEMAGIC 0x573264 /* version ID value */
/*
* hardcoded tuple descriptors. see include/catalog/pg_attribute.h
*/
static FormData_pg_attribute Desc_pg_class[Natts_pg_class] = {Schema_pg_class};
static FormData_pg_attribute Desc_pg_attribute[Natts_pg_attribute] = {Schema_pg_attribute};
static FormData_pg_attribute Desc_pg_proc[Natts_pg_proc] = {Schema_pg_proc};
static FormData_pg_attribute Desc_pg_type[Natts_pg_type] = {Schema_pg_type};
static FormData_pg_attribute Desc_pg_index[Natts_pg_index] = {Schema_pg_index};
/*
* Hash tables that index the relation cache
*
* We used to index the cache by both name and OID, but now there
* is only an index by OID.
*/
typedef struct relidcacheent
{
Oid reloid;
Relation reldesc;
} RelIdCacheEnt;
static HTAB *RelationIdCache;
/*
* This flag is false until we have prepared the critical relcache entries
* that are needed to do indexscans on the tables read by relcache building.
*/
bool criticalRelcachesBuilt = false;
/*
* This counter counts relcache inval events received since backend startup
* (but only for rels that are actually in cache). Presently, we use it only
* to detect whether data about to be written by write_relcache_init_file()
* might already be obsolete.
*/
static long relcacheInvalsReceived = 0L;
/*
* This list remembers the OIDs of the relations cached in the relcache
* init file.
*/
static List *initFileRelationIds = NIL;
/*
* This flag lets us optimize away work in AtEO(Sub)Xact_RelationCache().
*/
static bool need_eoxact_work = false;
/*
* macros to manipulate the lookup hashtables
*/
#define RelationCacheInsert(RELATION) \
do { \
RelIdCacheEnt *idhentry; bool found; \
idhentry = (RelIdCacheEnt*)hash_search(RelationIdCache, \
(void *) &(RELATION->rd_id), \
HASH_ENTER, \
&found); \
/* used to give notice if found -- now just keep quiet */ \
idhentry->reldesc = RELATION; \
} while(0)
#define RelationIdCacheLookup(ID, RELATION) \
do { \
RelIdCacheEnt *hentry; \
hentry = (RelIdCacheEnt*)hash_search(RelationIdCache, \ (void *) &(ID), HASH_FIND,NULL); \
if (hentry) \
RELATION = hentry->reldesc; \
else \
RELATION = NULL; \
} while(0)
#define RelationCacheDelete(RELATION) \
do { \
RelIdCacheEnt *idhentry; \
idhentry = (RelIdCacheEnt*)hash_search(RelationIdCache, \
(void *) &(RELATION->rd_id), \
HASH_REMOVE, NULL); \
if (idhentry == NULL) \
elog(WARNING, "trying to delete a rd_id reldesc that does not exist"); \
} while(0)
/*
* Special cache for opclass-related information
*
* Note: only default operators and support procs get cached, ie, those with
* lefttype = righttype = opcintype.
*/
typedef struct opclasscacheent
{
Oid opclassoid; /* lookup key: OID of opclass */
bool valid; /* set TRUE after successful fill-in */
StrategyNumber numStrats; /* max # of strategies (from pg_am) */
StrategyNumber numSupport; /* max # of support procs (from pg_am) */
Oid opcfamily; /* OID of opclass's family */
Oid opcintype; /* OID of opclass's declared input type */
Oid *operatorOids; /* strategy operators' OIDs */
RegProcedure *supportProcs; /* support procs */
} OpClassCacheEnt;
static HTAB *OpClassCache = NULL;
/* non-export function prototypes */
static void RelationClearRelation(Relation relation, bool rebuild);
static void RelationReloadIndexInfo(Relation relation);
static void RelationFlushRelation(Relation relation);
static bool load_relcache_init_file(void);
static void write_relcache_init_file(void);
static void write_item(const void *data, Size len, FILE *fp);
static void formrdesc(const char *relationName, Oid relationReltype,
bool hasoids, int natts, FormData_pg_attribute *att);
static HeapTuple ScanPgRelation(Oid targetRelId, bool indexOK);
static Relation AllocateRelationDesc(Relation relation, Form_pg_class relp);
static void RelationParseRelOptions(Relation relation, HeapTuple tuple);
static void RelationBuildTupleDesc(Relation relation);
static Relation RelationBuildDesc(Oid targetRelId, Relation oldrelation);
static void RelationInitPhysicalAddr(Relation relation);
static TupleDesc GetPgClassDescriptor(void);
static TupleDesc GetPgIndexDescriptor(void);
static void AttrDefaultFetch(Relation relation);
static void CheckConstraintFetch(Relation relation);
static List *insert_ordered_oid(List *list, Oid datum);
static void IndexSupportInitialize(oidvector *indclass,
Oid *indexOperator,
RegProcedure *indexSupport,
Oid *opFamily,
Oid *opcInType,
StrategyNumber maxStrategyNumber,
StrategyNumber maxSupportNumber, AttrNumber maxAttributeNumber);
static OpClassCacheEnt *LookupOpclassInfo(Oid operatorClassOid,
StrategyNumber numStrats,
StrategyNumber numSupport);
/*
* ScanPgRelation
*
* this is used by RelationBuildDesc to find a pg_class
* tuple matching targetRelId.
*
* NB: the returned tuple has been copied into palloc'd storage
* and must eventually be freed with heap_freetuple.
*/
static HeapTuple
ScanPgRelation(Oid targetRelId, bool indexOK)
{
HeapTuple pg_class_tuple;
Relation pg_class_desc;
SysScanDesc pg_class_scan;
ScanKeyData key[1];
/*
* form a scan key
*/
ScanKeyInit(&key[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(targetRelId));
/*
* Open pg_class and fetch a tuple. Force heap scan if we haven't yet
* built the critical relcache entries (this includes initdb and startup
* without a pg_internal.init file). The caller can also force a heap
* scan by setting indexOK == false.
*/
pg_class_desc = heap_open(RelationRelationId, AccessShareLock);
pg_class_scan = systable_beginscan(pg_class_desc, ClassOidIndexId,
indexOK && criticalRelcachesBuilt,
SnapshotNow,
1, key);
pg_class_tuple = systable_getnext(pg_class_scan);
/*
* Must copy tuple before releasing buffer.
*/
if (HeapTupleIsValid(pg_class_tuple))
pg_class_tuple = heap_copytuple(pg_class_tuple);
/* all done */
systable_endscan(pg_class_scan);
heap_close(pg_class_desc, AccessShareLock);
return pg_class_tuple;
}
/*
* AllocateRelationDesc
*
* This is used to allocate memory for a new relation descriptor
* and initialize the rd_rel field.
*
* If 'relation' is NULL, allocate a new RelationData object.
* If not, reuse the given object (that path is taken only when
* we have to rebuild a relcache entry during RelationClearRelation).
*/
static Relation
AllocateRelationDesc(Relation relation, Form_pg_class relp){
MemoryContext oldcxt;
Form_pg_class relationForm;
/* Relcache entries must live in CacheMemoryContext */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
/*
* allocate space for new relation descriptor, if needed
*/
if (relation == NULL)
relation = (Relation) palloc(sizeof(RelationData));
/*
* clear all fields of reldesc
*/
MemSet(relation, 0, sizeof(RelationData));
relation->rd_targblock = InvalidBlockNumber;
/* make sure relation is marked as having no open file yet */
relation->rd_smgr = NULL;
/*
* Copy the relation tuple form
*
* We only allocate space for the fixed fields, ie, CLASS_TUPLE_SIZE. The
* variable-length fields (relacl, reloptions) are NOT stored in the
* relcache --- there'd be little point in it, since we don't copy the
* tuple's nulls bitmap and hence wouldn't know if the values are valid.
* Bottom line is that relacl *cannot* be retrieved from the relcache. Get
* it from the syscache if you need it. The same goes for the original
* form of reloptions (however, we do store the parsed form of reloptions
* in rd_options).
*/
relationForm = (Form_pg_class) palloc(CLASS_TUPLE_SIZE);
memcpy(relationForm, relp, CLASS_TUPLE_SIZE);
/* initialize relation tuple form */
relation->rd_rel = relationForm;
/* and allocate attribute tuple form storage */
relation->rd_att = CreateTemplateTupleDesc(relationForm->relnatts,
relationForm->relhasoids);
/* which we mark as a reference-counted tupdesc */
relation->rd_att->tdrefcount = 1;
MemoryContextSwitchTo(oldcxt);
return relation;
}
/*
* RelationParseRelOptions
* Convert pg_class.reloptions into pre-parsed rd_options
*
* tuple is the real pg_class tuple (not rd_rel!) for relation
*
* Note: rd_rel and (if an index) rd_am must be valid already
*/
static void
RelationParseRelOptions(Relation relation, HeapTuple tuple)
{
Datum datum;
bool isnull;
bytea *options;
relation->rd_options = NULL;
/* Fall out if relkind should not have options */ switch (relation->rd_rel->relkind)
{
case RELKIND_RELATION:
case RELKIND_TOASTVALUE:
case RELKIND_UNCATALOGED:
case RELKIND_INDEX:
break;
default:
return;
}
/*
* Fetch reloptions from tuple; have to use a hardwired descriptor because
* we might not have any other for pg_class yet (consider executing this
* code for pg_class itself)
*/
datum = fastgetattr(tuple,
Anum_pg_class_reloptions,
GetPgClassDescriptor(),
&isnull);
if (isnull)
return;
/* Parse into appropriate format; don't error out here */
switch (relation->rd_rel->relkind)
{
case RELKIND_RELATION:
case RELKIND_TOASTVALUE:
case RELKIND_UNCATALOGED:
options = heap_reloptions(relation->rd_rel->relkind, datum,
false);
break;
case RELKIND_INDEX:
options = index_reloptions(relation->rd_am->amoptions, datum,
false);
break;
default:
Assert(false); /* can't get here */
options = NULL; /* keep compiler quiet */
break;
}
/* Copy parsed data into CacheMemoryContext */
if (options)
{
relation->rd_options = MemoryContextAlloc(CacheMemoryContext,
VARSIZE(options));
memcpy(relation->rd_options, options, VARSIZE(options));
}
}
/*
* RelationBuildTupleDesc
*
* Form the relation's tuple descriptor from information in
* the pg_attribute, pg_attrdef & pg_constraint system catalogs.
*/
static void
RelationBuildTupleDesc(Relation relation)
{
HeapTuple pg_attribute_tuple;
Relation pg_attribute_desc;
SysScanDesc pg_attribute_scan;
ScanKeyData skey[2];
int need;
TupleConstr *constr;
AttrDefault *attrdef = NULL;
int ndef = 0;
/* copy some fields from pg_class row to rd_att */ relation->rd_att->tdtypeid = relation->rd_rel->reltype;
relation->rd_att->tdtypmod = -1; /* unnecessary, but... */
relation->rd_att->tdhasoid = relation->rd_rel->relhasoids;
constr = (TupleConstr *) MemoryContextAlloc(CacheMemoryContext,
sizeof(TupleConstr));
constr->has_not_null = false;
/*
* Form a scan key that selects only user attributes (attnum > 0).
* (Eliminating system attribute rows at the index level is lots faster
* than fetching them.)
*/
ScanKeyInit(&skey[0],
Anum_pg_attribute_attrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
ScanKeyInit(&skey[1],
Anum_pg_attribute_attnum,
BTGreaterStrategyNumber, F_INT2GT,
Int16GetDatum(0));
/*
* Open pg_attribute and begin a scan. Force heap scan if we haven't yet
* built the critical relcache entries (this includes initdb and startup
* without a pg_internal.init file).
*/
pg_attribute_desc = heap_open(AttributeRelationId, AccessShareLock);
pg_attribute_scan = systable_beginscan(pg_attribute_desc,
AttributeRelidNumIndexId,
criticalRelcachesBuilt,
SnapshotNow,
2, skey);
/*
* add attribute data to relation->rd_att
*/
need = relation->rd_rel->relnatts;
while (HeapTupleIsValid(pg_attribute_tuple = systable_getnext(pg_attribute_scan)))
{
Form_pg_attribute attp;
attp = (Form_pg_attribute) GETSTRUCT(pg_attribute_tuple);
if (attp->attnum <= 0 ||
attp->attnum > relation->rd_rel->relnatts)
elog(ERROR, "invalid attribute number %d for %s",
attp->attnum, RelationGetRelationName(relation));
memcpy(relation->rd_att->attrs[attp->attnum - 1],
attp,
ATTRIBUTE_TUPLE_SIZE);
/* Update constraint/default info */
if (attp->attnotnull)
constr->has_not_null = true;
if (attp->atthasdef)
{
if (attrdef == NULL)
attrdef = (AttrDefault *)
MemoryContextAllocZero(CacheMemoryContext,
relation->rd_rel->relnatts *
sizeof(AttrDefault));
attrdef[ndef].adnum = attp->attnum;
attrdef[ndef].adbin = NULL;
ndef++;
}
need--; if (need == 0)
break;
}
/*
* end the scan and close the attribute relation
*/
systable_endscan(pg_attribute_scan);
heap_close(pg_attribute_desc, AccessShareLock);
if (need != 0)
elog(ERROR, "catalog is missing %d attribute(s) for relid %u",
need, RelationGetRelid(relation));
/*
* The attcacheoff values we read from pg_attribute should all be -1
* ("unknown"). Verify this if assert checking is on. They will be
* computed when and if needed during tuple access.
*/
#ifdef USE_ASSERT_CHECKING
{
int i;
for (i = 0; i < relation->rd_rel->relnatts; i++)
Assert(relation->rd_att->attrs[i]->attcacheoff == -1);
}
#endif
/*
* However, we can easily set the attcacheoff value for the first
* attribute: it must be zero. This eliminates the need for special cases
* for attnum=1 that used to exist in fastgetattr() and index_getattr().
*/
if (relation->rd_rel->relnatts > 0)
relation->rd_att->attrs[0]->attcacheoff = 0;
/*
* Set up constraint/default info
*/
if (constr->has_not_null || ndef > 0 || relation->rd_rel->relchecks)
{
relation->rd_att->constr = constr;
if (ndef > 0) /* DEFAULTs */
{
if (ndef < relation->rd_rel->relnatts)
constr->defval = (AttrDefault *)
repalloc(attrdef, ndef * sizeof(AttrDefault));
else
constr->defval = attrdef;
constr->num_defval = ndef;
AttrDefaultFetch(relation);
}
else
constr->num_defval = 0;
if (relation->rd_rel->relchecks > 0) /* CHECKs */
{
constr->num_check = relation->rd_rel->relchecks;
constr->check = (ConstrCheck *)
MemoryContextAllocZero(CacheMemoryContext,
constr->num_check * sizeof(ConstrCheck));
CheckConstraintFetch(relation);
}
else
constr->num_check = 0;
}
else
{
pfree(constr); relation->rd_att->constr = NULL;
}
}
/*
* RelationBuildRuleLock
*
* Form the relation's rewrite rules from information in
* the pg_rewrite system catalog.
*
* Note: The rule parsetrees are potentially very complex node structures.
* To allow these trees to be freed when the relcache entry is flushed,
* we make a private memory context to hold the RuleLock information for
* each relcache entry that has associated rules. The context is used
* just for rule info, not for any other subsidiary data of the relcache
* entry, because that keeps the update logic in RelationClearRelation()
* manageable. The other subsidiary data structures are simple enough
* to be easy to free explicitly, anyway.
*/
static void
RelationBuildRuleLock(Relation relation)
{
MemoryContext rulescxt;
MemoryContext oldcxt;
HeapTuple rewrite_tuple;
Relation rewrite_desc;
TupleDesc rewrite_tupdesc;
SysScanDesc rewrite_scan;
ScanKeyData key;
RuleLock *rulelock;
int numlocks;
RewriteRule **rules;
int maxlocks;
/*
* Make the private context. Parameters are set on the assumption that
* it'll probably not contain much data.
*/
rulescxt = AllocSetContextCreate(CacheMemoryContext,
RelationGetRelationName(relation),
ALLOCSET_SMALL_MINSIZE,
ALLOCSET_SMALL_INITSIZE,
ALLOCSET_SMALL_MAXSIZE);
relation->rd_rulescxt = rulescxt;
/*
* allocate an array to hold the rewrite rules (the array is extended if
* necessary)
*/
maxlocks = 4;
rules = (RewriteRule **)
MemoryContextAlloc(rulescxt, sizeof(RewriteRule *) * maxlocks);
numlocks = 0;
/*
* form a scan key
*/
ScanKeyInit(&key,
Anum_pg_rewrite_ev_class,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
/*
* open pg_rewrite and begin a scan
*
* Note: since we scan the rules using RewriteRelRulenameIndexId, we will
* be reading the rules in name order, except possibly during
* emergency-recovery operations (ie, IgnoreSystemIndexes). This in turn
* ensures that rules will be fired in name order.
*/ rewrite_desc = heap_open(RewriteRelationId, AccessShareLock);
rewrite_tupdesc = RelationGetDescr(rewrite_desc);
rewrite_scan = systable_beginscan(rewrite_desc,
RewriteRelRulenameIndexId,
true, SnapshotNow,
1, &key);
while (HeapTupleIsValid(rewrite_tuple = systable_getnext(rewrite_scan)))
{
Form_pg_rewrite rewrite_form = (Form_pg_rewrite) GETSTRUCT(rewrite_tuple);
bool isnull;
Datum rule_datum;
text *rule_text;
char *rule_str;
RewriteRule *rule;
rule = (RewriteRule *) MemoryContextAlloc(rulescxt,
sizeof(RewriteRule));
rule->ruleId = HeapTupleGetOid(rewrite_tuple);
rule->event = rewrite_form->ev_type - '0';
rule->attrno = rewrite_form->ev_attr;
rule->enabled = rewrite_form->ev_enabled;
rule->isInstead = rewrite_form->is_instead;
/*
* Must use heap_getattr to fetch ev_action and ev_qual. Also, the
* rule strings are often large enough to be toasted. To avoid
* leaking memory in the caller's context, do the detoasting here so
* we can free the detoasted version.
*/
rule_datum = heap_getattr(rewrite_tuple,
Anum_pg_rewrite_ev_action,
rewrite_tupdesc,
&isnull);
Assert(!isnull);
rule_text = DatumGetTextP(rule_datum);
rule_str = DatumGetCString(DirectFunctionCall1(textout,
PointerGetDatum(rule_text)));
oldcxt = MemoryContextSwitchTo(rulescxt);
rule->actions = (List *) stringToNode(rule_str);
MemoryContextSwitchTo(oldcxt);
pfree(rule_str);
if ((Pointer) rule_text != DatumGetPointer(rule_datum))
pfree(rule_text);
rule_datum = heap_getattr(rewrite_tuple,
Anum_pg_rewrite_ev_qual,
rewrite_tupdesc,
&isnull);
Assert(!isnull);
rule_text = DatumGetTextP(rule_datum);
rule_str = DatumGetCString(DirectFunctionCall1(textout,
PointerGetDatum(rule_text)));
oldcxt = MemoryContextSwitchTo(rulescxt);
rule->qual = (Node *) stringToNode(rule_str);
MemoryContextSwitchTo(oldcxt);
pfree(rule_str);
if ((Pointer) rule_text != DatumGetPointer(rule_datum))
pfree(rule_text);
/*
* We want the rule's table references to be checked as though by the
* table owner, not the user referencing the rule. Therefore, scan
* through the rule's actions and set the checkAsUser field on all
* rtable entries. We have to look at the qual as well, in case it
* contains sublinks.
*
* The reason for doing this when the rule is loaded, rather than when * it is stored, is that otherwise ALTER TABLE OWNER would have to
* grovel through stored rules to update checkAsUser fields. Scanning
* the rule tree during load is relatively cheap (compared to
* constructing it in the first place), so we do it here.
*/
setRuleCheckAsUser((Node *) rule->actions, relation->rd_rel->relowner);
setRuleCheckAsUser(rule->qual, relation->rd_rel->relowner);
if (numlocks >= maxlocks)
{
maxlocks *= 2;
rules = (RewriteRule **)
repalloc(rules, sizeof(RewriteRule *) * maxlocks);
}
rules[numlocks++] = rule;
}
/*
* end the scan and close the attribute relation
*/
systable_endscan(rewrite_scan);
heap_close(rewrite_desc, AccessShareLock);
/*
* form a RuleLock and insert into relation
*/
rulelock = (RuleLock *) MemoryContextAlloc(rulescxt, sizeof(RuleLock));
rulelock->numLocks = numlocks;
rulelock->rules = rules;
relation->rd_rules = rulelock;
}
/*
* equalRuleLocks
*
* Determine whether two RuleLocks are equivalent
*
* Probably this should be in the rules code someplace...
*/
static bool
equalRuleLocks(RuleLock *rlock1, RuleLock *rlock2)
{
int i;
/*
* As of 7.3 we assume the rule ordering is repeatable, because
* RelationBuildRuleLock should read 'em in a consistent order. So just
* compare corresponding slots.
*/
if (rlock1 != NULL)
{
if (rlock2 == NULL)
return false;
if (rlock1->numLocks != rlock2->numLocks)
return false;
for (i = 0; i < rlock1->numLocks; i++)
{
RewriteRule *rule1 = rlock1->rules[i];
RewriteRule *rule2 = rlock2->rules[i];
if (rule1->ruleId != rule2->ruleId)
return false;
if (rule1->event != rule2->event)
return false;
if (rule1->attrno != rule2->attrno)
return false;
if (rule1->isInstead != rule2->isInstead)
return false;
if (!equal(rule1->qual, rule2->qual)) return false;
if (!equal(rule1->actions, rule2->actions))
return false;
}
}
else if (rlock2 != NULL)
return false;
return true;
}
/* ----------------------------------
* RelationBuildDesc
*
* Build a relation descriptor --- either a new one, or by
* recycling the given old relation object. The latter case
* supports rebuilding a relcache entry without invalidating
* pointers to it.
*
* Returns NULL if no pg_class row could be found for the given relid
* (suggesting we are trying to access a just-deleted relation).
* Any other error is reported via elog.
* --------------------------------
*/
static Relation
RelationBuildDesc(Oid targetRelId, Relation oldrelation)
{
Relation relation;
Oid relid;
HeapTuple pg_class_tuple;
Form_pg_class relp;
MemoryContext oldcxt;
/*
* find the tuple in pg_class corresponding to the given relation id
*/
pg_class_tuple = ScanPgRelation(targetRelId, true);
/*
* if no such tuple exists, return NULL
*/
if (!HeapTupleIsValid(pg_class_tuple))
return NULL;
/*
* get information from the pg_class_tuple
*/
relid = HeapTupleGetOid(pg_class_tuple);
relp = (Form_pg_class) GETSTRUCT(pg_class_tuple);
/*
* allocate storage for the relation descriptor, and copy pg_class_tuple
* to relation->rd_rel.
*/
relation = AllocateRelationDesc(oldrelation, relp);
/*
* initialize the relation's relation id (relation->rd_id)
*/
RelationGetRelid(relation) = relid;
/*
* normal relations are not nailed into the cache; nor can a pre-existing
* relation be new. It could be temp though. (Actually, it could be new
* too, but it's okay to forget that fact if forced to flush the entry.)
*/
relation->rd_refcnt = 0;
relation->rd_isnailed = false;
relation->rd_createSubid = InvalidSubTransactionId;
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId; relation->rd_istemp = isTempNamespace(relation->rd_rel->relnamespace);
/*
* initialize the tuple descriptor (relation->rd_att).
*/
RelationBuildTupleDesc(relation);
/*
* Fetch rules and triggers that affect this relation
*/
if (relation->rd_rel->relhasrules)
RelationBuildRuleLock(relation);
else
{
relation->rd_rules = NULL;
relation->rd_rulescxt = NULL;
}
if (relation->rd_rel->reltriggers > 0)
RelationBuildTriggers(relation);
else
relation->trigdesc = NULL;
/*
* if it's an index, initialize index-related information
*/
if (OidIsValid(relation->rd_rel->relam))
RelationInitIndexAccessInfo(relation);
/* extract reloptions if any */
RelationParseRelOptions(relation, pg_class_tuple);
/*
* initialize the relation lock manager information
*/
RelationInitLockInfo(relation); /* see lmgr.c */
/*
* initialize physical addressing information for the relation
*/
RelationInitPhysicalAddr(relation);
/* make sure relation is marked as having no open file yet */
relation->rd_smgr = NULL;
/*
* now we can free the memory allocated for pg_class_tuple
*/
heap_freetuple(pg_class_tuple);
/*
* Insert newly created relation into relcache hash tables.
*/
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
RelationCacheInsert(relation);
MemoryContextSwitchTo(oldcxt);
/* It's fully valid */
relation->rd_isvalid = true;
return relation;
}
/*
* Initialize the physical addressing info (RelFileNode) for a relcache entry
*/
static void
RelationInitPhysicalAddr(Relation relation)
{
if (relation->rd_rel->reltablespace) relation->rd_node.spcNode = relation->rd_rel->reltablespace;
else
relation->rd_node.spcNode = MyDatabaseTableSpace;
if (relation->rd_rel->relisshared)
relation->rd_node.dbNode = InvalidOid;
else
relation->rd_node.dbNode = MyDatabaseId;
relation->rd_node.relNode = relation->rd_rel->relfilenode;
}
/*
* Initialize index-access-method support data for an index relation
*/
void
RelationInitIndexAccessInfo(Relation relation)
{
HeapTuple tuple;
Form_pg_am aform;
Datum indclassDatum;
Datum indoptionDatum;
bool isnull;
oidvector *indclass;
int2vector *indoption;
MemoryContext indexcxt;
MemoryContext oldcontext;
int natts;
uint16 amstrategies;
uint16 amsupport;
/*
* Make a copy of the pg_index entry for the index. Since pg_index
* contains variable-length and possibly-null fields, we have to do this
* honestly rather than just treating it as a Form_pg_index struct.
*/
tuple = SearchSysCache(INDEXRELID,
ObjectIdGetDatum(RelationGetRelid(relation)),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for index %u",
RelationGetRelid(relation));
oldcontext = MemoryContextSwitchTo(CacheMemoryContext);
relation->rd_indextuple = heap_copytuple(tuple);
relation->rd_index = (Form_pg_index) GETSTRUCT(relation->rd_indextuple);
MemoryContextSwitchTo(oldcontext);
ReleaseSysCache(tuple);
/*
* Make a copy of the pg_am entry for the index's access method
*/
tuple = SearchSysCache(AMOID,
ObjectIdGetDatum(relation->rd_rel->relam),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for access method %u",
relation->rd_rel->relam);
aform = (Form_pg_am) MemoryContextAlloc(CacheMemoryContext, sizeof *aform);
memcpy(aform, GETSTRUCT(tuple), sizeof *aform);
ReleaseSysCache(tuple);
relation->rd_am = aform;
natts = relation->rd_rel->relnatts;
if (natts != relation->rd_index->indnatts)
elog(ERROR, "relnatts disagrees with indnatts for index %u",
RelationGetRelid(relation));
amstrategies = aform->amstrategies;
amsupport = aform->amsupport;
/*
* Make the private context to hold index access info. The reason we need
* a context, and not just a couple of pallocs, is so that we won't leak * any subsidiary info attached to fmgr lookup records.
*
* Context parameters are set on the assumption that it'll probably not
* contain much data.
*/
indexcxt = AllocSetContextCreate(CacheMemoryContext,
RelationGetRelationName(relation),
ALLOCSET_SMALL_MINSIZE,
ALLOCSET_SMALL_INITSIZE,
ALLOCSET_SMALL_MAXSIZE);
relation->rd_indexcxt = indexcxt;
/*
* Allocate arrays to hold data
*/
relation->rd_aminfo = (RelationAmInfo *)
MemoryContextAllocZero(indexcxt, sizeof(RelationAmInfo));
relation->rd_opfamily = (Oid *)
MemoryContextAllocZero(indexcxt, natts * sizeof(Oid));
relation->rd_opcintype = (Oid *)
MemoryContextAllocZero(indexcxt, natts * sizeof(Oid));
if (amstrategies > 0)
relation->rd_operator = (Oid *)
MemoryContextAllocZero(indexcxt,
natts * amstrategies * sizeof(Oid));
else
relation->rd_operator = NULL;
if (amsupport > 0)
{
int nsupport = natts * amsupport;
relation->rd_support = (RegProcedure *)
MemoryContextAllocZero(indexcxt, nsupport * sizeof(RegProcedure));
relation->rd_supportinfo = (FmgrInfo *)
MemoryContextAllocZero(indexcxt, nsupport * sizeof(FmgrInfo));
}
else
{
relation->rd_support = NULL;
relation->rd_supportinfo = NULL;
}
relation->rd_indoption = (int16 *)
MemoryContextAllocZero(indexcxt, natts * sizeof(int16));
/*
* indclass cannot be referenced directly through the C struct, because it
* comes after the variable-width indkey field. Must extract the
* datum the hard way...
*/
indclassDatum = fastgetattr(relation->rd_indextuple,
Anum_pg_index_indclass,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
indclass = (oidvector *) DatumGetPointer(indclassDatum);
/*
* Fill the operator and support procedure OID arrays, as well as the
* info about opfamilies and opclass input types. (aminfo and
* supportinfo are left as zeroes, and are filled on-the-fly when used)
*/
IndexSupportInitialize(indclass,
relation->rd_operator, relation->rd_support,
relation->rd_opfamily, relation->rd_opcintype,
amstrategies, amsupport, natts);
/*
* Similarly extract indoption and copy it to the cache entry
*/
indoptionDatum = fastgetattr(relation->rd_indextuple,
Anum_pg_index_indoption,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
indoption = (int2vector *) DatumGetPointer(indoptionDatum);
memcpy(relation->rd_indoption, indoption->values, natts * sizeof(int16));
/*
* expressions and predicate cache will be filled later
*/
relation->rd_indexprs = NIL;
relation->rd_indpred = NIL;
relation->rd_amcache = NULL;
}
/*
* IndexSupportInitialize
* Initializes an index's cached opclass information,
* given the index's pg_index.indclass entry.
*
* Data is returned into *indexOperator, *indexSupport, *opFamily, and
* *opcInType, which are arrays allocated by the caller.
*
* The caller also passes maxStrategyNumber, maxSupportNumber, and
* maxAttributeNumber, since these indicate the size of the arrays
* it has allocated --- but in practice these numbers must always match
* those obtainable from the system catalog entries for the index and
* access method.
*/
static void
IndexSupportInitialize(oidvector *indclass,
Oid *indexOperator,
RegProcedure *indexSupport,
Oid *opFamily,
Oid *opcInType,
StrategyNumber maxStrategyNumber,
StrategyNumber maxSupportNumber,
AttrNumber maxAttributeNumber)
{
int attIndex;
for (attIndex = 0; attIndex < maxAttributeNumber; attIndex++)
{
OpClassCacheEnt *opcentry;
if (!OidIsValid(indclass->values[attIndex]))
elog(ERROR, "bogus pg_index tuple");
/* look up the info for this opclass, using a cache */
opcentry = LookupOpclassInfo(indclass->values[attIndex],
maxStrategyNumber,
maxSupportNumber);
/* copy cached data into relcache entry */
opFamily[attIndex] = opcentry->opcfamily;
opcInType[attIndex] = opcentry->opcintype;
if (maxStrategyNumber > 0)
memcpy(&indexOperator[attIndex * maxStrategyNumber],
opcentry->operatorOids,
maxStrategyNumber * sizeof(Oid));
if (maxSupportNumber > 0)
memcpy(&indexSupport[attIndex * maxSupportNumber],
opcentry->supportProcs,
maxSupportNumber * sizeof(RegProcedure));
}
}
/*
* LookupOpclassInfo
*
* This routine maintains a per-opclass cache of the information needed
* by IndexSupportInitialize(). This is more efficient than relying on
* the catalog cache, because we can load all the info about a particular
* opclass in a single indexscan of pg_amproc or pg_amop.
*
* The information from pg_am about expected range of strategy and support
* numbers is passed in, rather than being looked up, mainly because the
* caller will have it already.
*
* XXX There isn't any provision for flushing the cache. However, there
* isn't any provision for flushing relcache entries when opclass info
* changes, either :-(
*/
static OpClassCacheEnt *
LookupOpclassInfo(Oid operatorClassOid,
StrategyNumber numStrats,
StrategyNumber numSupport)
{
OpClassCacheEnt *opcentry;
bool found;
Relation rel;
SysScanDesc scan;
ScanKeyData skey[3];
HeapTuple htup;
bool indexOK;
if (OpClassCache == NULL)
{
/* First time through: initialize the opclass cache */
HASHCTL ctl;
if (!CacheMemoryContext)
CreateCacheMemoryContext();
MemSet(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(Oid);
ctl.entrysize = sizeof(OpClassCacheEnt);
ctl.hash = oid_hash;
OpClassCache = hash_create("Operator class cache", 64,
&ctl, HASH_ELEM | HASH_FUNCTION);
}
opcentry = (OpClassCacheEnt *) hash_search(OpClassCache,
(void *) &operatorClassOid,
HASH_ENTER, &found);
if (found && opcentry->valid)
{
/* Already made an entry for it */
Assert(numStrats == opcentry->numStrats);
Assert(numSupport == opcentry->numSupport);
return opcentry;
}
/* Need to fill in new entry */
opcentry->valid = false; /* until known OK */
opcentry->numStrats = numStrats;
opcentry->numSupport = numSupport;
if (numStrats > 0)
opcentry->operatorOids = (Oid *)
MemoryContextAllocZero(CacheMemoryContext,
numStrats * sizeof(Oid));
else
opcentry->operatorOids = NULL;
if (numSupport > 0)
opcentry->supportProcs = (RegProcedure *)
MemoryContextAllocZero(CacheMemoryContext,
numSupport * sizeof(RegProcedure));
else
opcentry->supportProcs = NULL;
/*
* To avoid infinite recursion during startup, force heap scans if we're
* looking up info for the opclasses used by the indexes we would like to
* reference here.
*/
indexOK = criticalRelcachesBuilt ||
(operatorClassOid != OID_BTREE_OPS_OID &&
operatorClassOid != INT2_BTREE_OPS_OID);
/*
* We have to fetch the pg_opclass row to determine its opfamily and
* opcintype, which are needed to look up the operators and functions.
* It'd be convenient to use the syscache here, but that probably doesn't
* work while bootstrapping.
*/
ScanKeyInit(&skey[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(operatorClassOid));
rel = heap_open(OperatorClassRelationId, AccessShareLock);
scan = systable_beginscan(rel, OpclassOidIndexId, indexOK,
SnapshotNow, 1, skey);
if (HeapTupleIsValid(htup = systable_getnext(scan)))
{
Form_pg_opclass opclassform = (Form_pg_opclass) GETSTRUCT(htup);
opcentry->opcfamily = opclassform->opcfamily;
opcentry->opcintype = opclassform->opcintype;
}
else
elog(ERROR, "could not find tuple for opclass %u", operatorClassOid);
systable_endscan(scan);
heap_close(rel, AccessShareLock);
/*
* Scan pg_amop to obtain operators for the opclass. We only fetch the
* default ones (those with lefttype = righttype = opcintype).
*/
if (numStrats > 0)
{
ScanKeyInit(&skey[0],
Anum_pg_amop_amopfamily,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(opcentry->opcfamily));
ScanKeyInit(&skey[1],
Anum_pg_amop_amoplefttype,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(opcentry->opcintype));
ScanKeyInit(&skey[2],
Anum_pg_amop_amoprighttype,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(opcentry->opcintype));
rel = heap_open(AccessMethodOperatorRelationId, AccessShareLock);
scan = systable_beginscan(rel, AccessMethodStrategyIndexId, indexOK,
SnapshotNow, 3, skey);
while (HeapTupleIsValid(htup = systable_getnext(scan)))
{
Form_pg_amop amopform = (Form_pg_amop) GETSTRUCT(htup);
if (amopform->amopstrategy <= 0 ||
(StrategyNumber) amopform->amopstrategy > numStrats)
elog(ERROR, "invalid amopstrategy number %d for opclass %u",
amopform->amopstrategy, operatorClassOid);
opcentry->operatorOids[amopform->amopstrategy - 1] =
amopform->amopopr;
}
systable_endscan(scan);
heap_close(rel, AccessShareLock);
}
/*
* Scan pg_amproc to obtain support procs for the opclass. We only fetch
* the default ones (those with lefttype = righttype = opcintype).
*/
if (numSupport > 0)
{
ScanKeyInit(&skey[0],
Anum_pg_amproc_amprocfamily,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(opcentry->opcfamily));
ScanKeyInit(&skey[1],
Anum_pg_amproc_amproclefttype,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(opcentry->opcintype));
ScanKeyInit(&skey[2],
Anum_pg_amproc_amprocrighttype,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(opcentry->opcintype));
rel = heap_open(AccessMethodProcedureRelationId, AccessShareLock);
scan = systable_beginscan(rel, AccessMethodProcedureIndexId, indexOK,
SnapshotNow, 3, skey);
while (HeapTupleIsValid(htup = systable_getnext(scan)))
{
Form_pg_amproc amprocform = (Form_pg_amproc) GETSTRUCT(htup);
if (amprocform->amprocnum <= 0 ||
(StrategyNumber) amprocform->amprocnum > numSupport)
elog(ERROR, "invalid amproc number %d for opclass %u",
amprocform->amprocnum, operatorClassOid);
opcentry->supportProcs[amprocform->amprocnum - 1] =
amprocform->amproc;
}
systable_endscan(scan);
heap_close(rel, AccessShareLock);
}
opcentry->valid = true;
return opcentry;
}
/*
* formrdesc
*
* This is a special cut-down version of RelationBuildDesc()
* used by RelationCacheInitializePhase2() in initializing the relcache.
* The relation descriptor is built just from the supplied parameters,
* without actually looking at any system table entries. We cheat
* quite a lot since we only need to work for a few basic system
* catalogs.
*
* formrdesc is currently used for: pg_class, pg_attribute, pg_proc,
* and pg_type (see RelationCacheInitializePhase2).
*
* Note that these catalogs can't have constraints (except attnotnull), * default values, rules, or triggers, since we don't cope with any of that.
*
* NOTE: we assume we are already switched into CacheMemoryContext.
*/
static void
formrdesc(const char *relationName, Oid relationReltype,
bool hasoids, int natts, FormData_pg_attribute *att)
{
Relation relation;
int i;
bool has_not_null;
/*
* allocate new relation desc, clear all fields of reldesc
*/
relation = (Relation) palloc0(sizeof(RelationData));
relation->rd_targblock = InvalidBlockNumber;
/* make sure relation is marked as having no open file yet */
relation->rd_smgr = NULL;
/*
* initialize reference count: 1 because it is nailed in cache
*/
relation->rd_refcnt = 1;
/*
* all entries built with this routine are nailed-in-cache; none are for
* new or temp relations.
*/
relation->rd_isnailed = true;
relation->rd_createSubid = InvalidSubTransactionId;
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
relation->rd_istemp = false;
/*
* initialize relation tuple form
*
* The data we insert here is pretty incomplete/bogus, but it'll serve to
* get us launched. RelationCacheInitializePhase2() will read the real
* data from pg_class and replace what we've done here.
*/
relation->rd_rel = (Form_pg_class) palloc0(CLASS_TUPLE_SIZE);
namestrcpy(&relation->rd_rel->relname, relationName);
relation->rd_rel->relnamespace = PG_CATALOG_NAMESPACE;
relation->rd_rel->reltype = relationReltype;
/*
* It's important to distinguish between shared and non-shared relations,
* even at bootstrap time, to make sure we know where they are stored. At
* present, all relations that formrdesc is used for are not shared.
*/
relation->rd_rel->relisshared = false;
relation->rd_rel->relpages = 1;
relation->rd_rel->reltuples = 1;
relation->rd_rel->relkind = RELKIND_RELATION;
relation->rd_rel->relhasoids = hasoids;
relation->rd_rel->relnatts = (int16) natts;
/*
* initialize attribute tuple form
*
* Unlike the case with the relation tuple, this data had better be right
* because it will never be replaced. The input values must be correctly
* defined by macros in src/include/catalog/ headers.
*/
relation->rd_att = CreateTemplateTupleDesc(natts, hasoids);
relation->rd_att->tdrefcount = 1; /* mark as refcounted */
relation->rd_att->tdtypeid = relationReltype;
relation->rd_att->tdtypmod = -1; /* unnecessary, but... */
/*
* initialize tuple desc info
*/
has_not_null = false;
for (i = 0; i < natts; i++)
{
memcpy(relation->rd_att->attrs[i],
&att[i],
ATTRIBUTE_TUPLE_SIZE);
has_not_null |= att[i].attnotnull;
/* make sure attcacheoff is valid */
relation->rd_att->attrs[i]->attcacheoff = -1;
}
/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
relation->rd_att->attrs[0]->attcacheoff = 0;
/* mark not-null status */
if (has_not_null)
{
TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
constr->has_not_null = true;
relation->rd_att->constr = constr;
}
/*
* initialize relation id from info in att array (my, this is ugly)
*/
RelationGetRelid(relation) = relation->rd_att->attrs[0]->attrelid;
relation->rd_rel->relfilenode = RelationGetRelid(relation);
/*
* initialize the relation lock manager information
*/
RelationInitLockInfo(relation); /* see lmgr.c */
/*
* initialize physical addressing information for the relation
*/
RelationInitPhysicalAddr(relation);
/*
* initialize the rel-has-index flag, using hardwired knowledge
*/
if (IsBootstrapProcessingMode())
{
/* In bootstrap mode, we have no indexes */
relation->rd_rel->relhasindex = false;
}
else
{
/* Otherwise, all the rels formrdesc is used for have indexes */
relation->rd_rel->relhasindex = true;
}
/*
* add new reldesc to relcache
*/
RelationCacheInsert(relation);
/* It's fully valid */
relation->rd_isvalid = true;
}
/* ----------------------------------------------------------------
* Relation Descriptor Lookup Interface
* ----------------------------------------------------------------
*/
/*
* RelationIdGetRelation
*
* Lookup a reldesc by OID; make one if not already in cache.
*
* Returns NULL if no pg_class row could be found for the given relid
* (suggesting we are trying to access a just-deleted relation).
* Any other error is reported via elog.
*
* NB: caller should already have at least AccessShareLock on the
* relation ID, else there are nasty race conditions.
*
* NB: relation ref count is incremented, or set to 1 if new entry.
* Caller should eventually decrement count. (Usually,
* that happens by calling RelationClose().)
*/
Relation
RelationIdGetRelation(Oid relationId)
{
Relation rd;
/*
* first try to find reldesc in the cache
*/
RelationIdCacheLookup(relationId, rd);
if (RelationIsValid(rd))
{
RelationIncrementReferenceCount(rd);
/* revalidate nailed index if necessary */
if (!rd->rd_isvalid)
RelationReloadIndexInfo(rd);
return rd;
}
/*
* no reldesc in the cache, so have RelationBuildDesc() build one and add
* it.
*/
rd = RelationBuildDesc(relationId, NULL);
if (RelationIsValid(rd))
RelationIncrementReferenceCount(rd);
return rd;
}
/* ----------------------------------------------------------------
* cache invalidation support routines
* ----------------------------------------------------------------
*/
/*
* RelationIncrementReferenceCount
* Increments relation reference count.
*
* Note: bootstrap mode has its own weird ideas about relation refcount
* behavior; we ought to fix it someday, but for now, just disable
* reference count ownership tracking in bootstrap mode.
*/
void
RelationIncrementReferenceCount(Relation rel)
{
ResourceOwnerEnlargeRelationRefs(CurrentResourceOwner);
rel->rd_refcnt += 1;
if (!IsBootstrapProcessingMode())
ResourceOwnerRememberRelationRef(CurrentResourceOwner, rel);}
/*
* RelationDecrementReferenceCount
* Decrements relation reference count.
*/
void
RelationDecrementReferenceCount(Relation rel)
{
Assert(rel->rd_refcnt > 0);
rel->rd_refcnt -= 1;
if (!IsBootstrapProcessingMode())
ResourceOwnerForgetRelationRef(CurrentResourceOwner, rel);
}
/*
* RelationClose - close an open relation
*
* Actually, we just decrement the refcount.
*
* NOTE: if compiled with -DRELCACHE_FORCE_RELEASE then relcache entries
* will be freed as soon as their refcount goes to zero. In combination
* with aset.c's CLOBBER_FREED_MEMORY option, this provides a good test
* to catch references to already-released relcache entries. It slows
* things down quite a bit, however.
*/
void
RelationClose(Relation relation)
{
/* Note: no locking manipulations needed */
RelationDecrementReferenceCount(relation);
#ifdef RELCACHE_FORCE_RELEASE
if (RelationHasReferenceCountZero(relation) &&
relation->rd_createSubid == InvalidSubTransactionId &&
relation->rd_newRelfilenodeSubid == InvalidSubTransactionId)
RelationClearRelation(relation, false);
#endif
}
/*
* RelationReloadIndexInfo - reload minimal information for an open index
*
* This function is used only for indexes. A relcache inval on an index
* can mean that its pg_class or pg_index row changed. There are only
* very limited changes that are allowed to an existing index's schema,
* so we can update the relcache entry without a complete rebuild; which
* is fortunate because we can't rebuild an index entry that is "nailed"
* and/or in active use. We support full replacement of the pg_class row,
* as well as updates of a few simple fields of the pg_index row.
*
* We can't necessarily reread the catalog rows right away; we might be
* in a failed transaction when we receive the SI notification. If so,
* RelationClearRelation just marks the entry as invalid by setting
* rd_isvalid to false. This routine is called to fix the entry when it
* is next needed.
*/
static void
RelationReloadIndexInfo(Relation relation)
{
bool indexOK;
HeapTuple pg_class_tuple;
Form_pg_class relp;
/* Should be called only for invalidated indexes */
Assert(relation->rd_rel->relkind == RELKIND_INDEX &&
!relation->rd_isvalid);
/* Should be closed at smgr level */
Assert(relation->rd_smgr == NULL);
/*
* Read the pg_class row
*
* Don't try to use an indexscan of pg_class_oid_index to reload the info
* for pg_class_oid_index ...
*/
indexOK = (RelationGetRelid(relation) != ClassOidIndexId);
pg_class_tuple = ScanPgRelation(RelationGetRelid(relation), indexOK);
if (!HeapTupleIsValid(pg_class_tuple))
elog(ERROR, "could not find pg_class tuple for index %u",
RelationGetRelid(relation));
relp = (Form_pg_class) GETSTRUCT(pg_class_tuple);
memcpy(relation->rd_rel, relp, CLASS_TUPLE_SIZE);
/* Reload reloptions in case they changed */
if (relation->rd_options)
pfree(relation->rd_options);
RelationParseRelOptions(relation, pg_class_tuple);
/* done with pg_class tuple */
heap_freetuple(pg_class_tuple);
/* We must recalculate physical address in case it changed */
RelationInitPhysicalAddr(relation);
/* Make sure targblock is reset in case rel was truncated */
relation->rd_targblock = InvalidBlockNumber;
/* Must free any AM cached data, too */
if (relation->rd_amcache)
pfree(relation->rd_amcache);
relation->rd_amcache = NULL;
/*
* For a non-system index, there are fields of the pg_index row that are
* allowed to change, so re-read that row and update the relcache entry.
* Most of the info derived from pg_index (such as support function lookup
* info) cannot change, and indeed the whole point of this routine is to
* update the relcache entry without clobbering that data; so wholesale
* replacement is not appropriate.
*/
if (!IsSystemRelation(relation))
{
HeapTuple tuple;
Form_pg_index index;
tuple = SearchSysCache(INDEXRELID,
ObjectIdGetDatum(RelationGetRelid(relation)),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for index %u",
RelationGetRelid(relation));
index = (Form_pg_index) GETSTRUCT(tuple);
relation->rd_index->indisvalid = index->indisvalid;
ReleaseSysCache(tuple);
}
/* Okay, now it's valid again */
relation->rd_isvalid = true;
}
/*
* RelationClearRelation
*
* Physically blow away a relation cache entry, or reset it and rebuild
* it from scratch (that is, from catalog entries). The latter path is
* usually used when we are notified of a change to an open relation
* (one with refcount > 0). However, this routine just does whichever
* it's told to do; callers must determine which they want.
*/
static void
RelationClearRelation(Relation relation, bool rebuild)
{ Oid old_reltype = relation->rd_rel->reltype;
MemoryContext oldcxt;
/*
* Make sure smgr and lower levels close the relation's files, if they
* weren't closed already. If the relation is not getting deleted, the
* next smgr access should reopen the files automatically. This ensures
* that the low-level file access state is updated after, say, a vacuum
* truncation.
*/
RelationCloseSmgr(relation);
/*
* Never, never ever blow away a nailed-in system relation, because we'd
* be unable to recover. However, we must reset rd_targblock, in case we
* got called because of a relation cache flush that was triggered by
* VACUUM.
*
* If it's a nailed index, then we need to re-read the pg_class row to see
* if its relfilenode changed. We can't necessarily do that here, because
* we might be in a failed transaction. We assume it's okay to do it if
* there are open references to the relcache entry (cf notes for
* AtEOXact_RelationCache). Otherwise just mark the entry as possibly
* invalid, and it'll be fixed when next opened.
*/
if (relation->rd_isnailed)
{
relation->rd_targblock = InvalidBlockNumber;
if (relation->rd_rel->relkind == RELKIND_INDEX)
{
relation->rd_isvalid = false; /* needs to be revalidated */
if (relation->rd_refcnt > 1)
RelationReloadIndexInfo(relation);
}
return;
}
/*
* Even non-system indexes should not be blown away if they are open and
* have valid index support information. This avoids problems with active
* use of the index support information. As with nailed indexes, we
* re-read the pg_class row to handle possible physical relocation of the
* index, and we check for pg_index updates too.
*/
if (relation->rd_rel->relkind == RELKIND_INDEX &&
relation->rd_refcnt > 0 &&
relation->rd_indexcxt != NULL)
{
relation->rd_isvalid = false; /* needs to be revalidated */
RelationReloadIndexInfo(relation);
return;
}
/*
* Remove relation from hash tables
*
* Note: we might be reinserting it momentarily, but we must not have it
* visible in the hash tables until it's valid again, so don't try to
* optimize this away...
*/
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
RelationCacheDelete(relation);
MemoryContextSwitchTo(oldcxt);
/* Clear out catcache's entries for this relation */
CatalogCacheFlushRelation(RelationGetRelid(relation));
/*
* Free all the subsidiary data structures of the relcache entry. We
* cannot free rd_att if we are trying to rebuild the entry, however, * because pointers to it may be cached in various places. The rule
* manager might also have pointers into the rewrite rules. So to begin
* with, we can only get rid of these fields:
*/
FreeTriggerDesc(relation->trigdesc);
if (relation->rd_indextuple)
pfree(relation->rd_indextuple);
if (relation->rd_am)
pfree(relation->rd_am);
if (relation->rd_rel)
pfree(relation->rd_rel);
if (relation->rd_options)
pfree(relation->rd_options);
list_free(relation->rd_indexlist);
if (relation->rd_indexcxt)
MemoryContextDelete(relation->rd_indexcxt);
/*
* If we're really done with the relcache entry, blow it away. But if
* someone is still using it, reconstruct the whole deal without moving
* the physical RelationData record (so that the someone's pointer is
* still valid).
*/
if (!rebuild)
{
/* ok to zap remaining substructure */
flush_rowtype_cache(old_reltype);
/* can't use DecrTupleDescRefCount here */
Assert(relation->rd_att->tdrefcount > 0);
if (--relation->rd_att->tdrefcount == 0)
FreeTupleDesc(relation->rd_att);
if (relation->rd_rulescxt)
MemoryContextDelete(relation->rd_rulescxt);
pfree(relation);
}
else
{
/*
* When rebuilding an open relcache entry, must preserve ref count and
* rd_createSubid/rd_newRelfilenodeSubid state. Also attempt to
* preserve the tupledesc and rewrite-rule substructures in place.
* (Note: the refcount mechanism for tupledescs may eventually ensure
* that we don't really need to preserve the tupledesc in-place, but
* for now there are still a lot of places that assume an open rel's
* tupledesc won't move.)
*
* Note that this process does not touch CurrentResourceOwner; which
* is good because whatever ref counts the entry may have do not
* necessarily belong to that resource owner.
*/
Oid save_relid = RelationGetRelid(relation);
int old_refcnt = relation->rd_refcnt;
SubTransactionId old_createSubid = relation->rd_createSubid;
SubTransactionId old_newRelfilenodeSubid = relation->rd_newRelfilenodeSubid;
TupleDesc old_att = relation->rd_att;
RuleLock *old_rules = relation->rd_rules;
MemoryContext old_rulescxt = relation->rd_rulescxt;
if (RelationBuildDesc(save_relid, relation) != relation)
{
/* Should only get here if relation was deleted */
flush_rowtype_cache(old_reltype);
Assert(old_att->tdrefcount > 0);
if (--old_att->tdrefcount == 0)
FreeTupleDesc(old_att);
if (old_rulescxt)
MemoryContextDelete(old_rulescxt);
pfree(relation);
elog(ERROR, "relation %u deleted while still in use", save_relid);
} relation->rd_refcnt = old_refcnt;
relation->rd_createSubid = old_createSubid;
relation->rd_newRelfilenodeSubid = old_newRelfilenodeSubid;
if (equalTupleDescs(old_att, relation->rd_att))
{
/* needn't flush typcache here */
Assert(relation->rd_att->tdrefcount == 1);
if (--relation->rd_att->tdrefcount == 0)
FreeTupleDesc(relation->rd_att);
relation->rd_att = old_att;
}
else
{
flush_rowtype_cache(old_reltype);
Assert(old_att->tdrefcount > 0);
if (--old_att->tdrefcount == 0)
FreeTupleDesc(old_att);
}
if (equalRuleLocks(old_rules, relation->rd_rules))
{
if (relation->rd_rulescxt)
MemoryContextDelete(relation->rd_rulescxt);
relation->rd_rules = old_rules;
relation->rd_rulescxt = old_rulescxt;
}
else
{
if (old_rulescxt)
MemoryContextDelete(old_rulescxt);
}
}
}
/*
* RelationFlushRelation
*
* Rebuild the relation if it is open (refcount > 0), else blow it away.
*/
static void
RelationFlushRelation(Relation relation)
{
bool rebuild;
if (relation->rd_createSubid != InvalidSubTransactionId ||
relation->rd_newRelfilenodeSubid != InvalidSubTransactionId)
{
/*
* New relcache entries are always rebuilt, not flushed; else we'd
* forget the "new" status of the relation, which is a useful
* optimization to have. Ditto for the new-relfilenode status.
*/
rebuild = true;
}
else
{
/*
* Pre-existing rels can be dropped from the relcache if not open.
*/
rebuild = !RelationHasReferenceCountZero(relation);
}
RelationClearRelation(relation, rebuild);
}
/*
* RelationForgetRelation - unconditionally remove a relcache entry
*
* External interface for destroying a relcache entry when we
* drop the relation. */
void
RelationForgetRelation(Oid rid)
{
Relation relation;
RelationIdCacheLookup(rid, relation);
if (!PointerIsValid(relation))
return; /* not in cache, nothing to do */
if (!RelationHasReferenceCountZero(relation))
elog(ERROR, "relation %u is still open", rid);
/* Unconditionally destroy the relcache entry */
RelationClearRelation(relation, false);
}
/*
* RelationCacheInvalidateEntry
*
* This routine is invoked for SI cache flush messages.
*
* Any relcache entry matching the relid must be flushed. (Note: caller has
* already determined that the relid belongs to our database or is a shared
* relation.)
*
* We used to skip local relations, on the grounds that they could
* not be targets of cross-backend SI update messages; but it seems
* safer to process them, so that our *own* SI update messages will
* have the same effects during CommandCounterIncrement for both
* local and nonlocal relations.
*/
void
RelationCacheInvalidateEntry(Oid relationId)
{
Relation relation;
RelationIdCacheLookup(relationId, relation);
if (PointerIsValid(relation))
{
relcacheInvalsReceived++;
RelationFlushRelation(relation);
}
}
/*
* RelationCacheInvalidate
* Blow away cached relation descriptors that have zero reference counts,
* and rebuild those with positive reference counts. Also reset the smgr
* relation cache.
*
* This is currently used only to recover from SI message buffer overflow,
* so we do not touch new-in-transaction relations; they cannot be targets
* of cross-backend SI updates (and our own updates now go through a
* separate linked list that isn't limited by the SI message buffer size).
* Likewise, we need not discard new-relfilenode-in-transaction hints,
* since any invalidation of those would be a local event.
*
* We do this in two phases: the first pass deletes deletable items, and
* the second one rebuilds the rebuildable items. This is essential for
* safety, because hash_seq_search only copes with concurrent deletion of
* the element it is currently visiting. If a second SI overflow were to
* occur while we are walking the table, resulting in recursive entry to
* this routine, we could crash because the inner invocation blows away
* the entry next to be visited by the outer scan. But this way is OK,
* because (a) during the first pass we won't process any more SI messages,
* so hash_seq_search will complete safely; (b) during the second pass we
* only hold onto pointers to nondeletable entries. *
* The two-phase approach also makes it easy to ensure that we process
* nailed-in-cache indexes before other nondeletable items, and that we
* process pg_class_oid_index first of all. In scenarios where a nailed
* index has been given a new relfilenode, we have to detect that update
* before the nailed index is used in reloading any other relcache entry.
*/
void
RelationCacheInvalidate(void)
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
Relation relation;
List *rebuildFirstList = NIL;
List *rebuildList = NIL;
ListCell *l;
/* Phase 1 */
hash_seq_init(&status, RelationIdCache);
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
relation = idhentry->reldesc;
/* Must close all smgr references to avoid leaving dangling ptrs */
RelationCloseSmgr(relation);
/* Ignore new relations, since they are never SI targets */
if (relation->rd_createSubid != InvalidSubTransactionId)
continue;
relcacheInvalsReceived++;
if (RelationHasReferenceCountZero(relation))
{
/* Delete this entry immediately */
Assert(!relation->rd_isnailed);
RelationClearRelation(relation, false);
}
else
{
/*
* Add this entry to list of stuff to rebuild in second pass.
* pg_class_oid_index goes on the front of rebuildFirstList, other
* nailed indexes on the back, and everything else into
* rebuildList (in no particular order).
*/
if (relation->rd_isnailed &&
relation->rd_rel->relkind == RELKIND_INDEX)
{
if (RelationGetRelid(relation) == ClassOidIndexId)
rebuildFirstList = lcons(relation, rebuildFirstList);
else
rebuildFirstList = lappend(rebuildFirstList, relation);
}
else
rebuildList = lcons(relation, rebuildList);
}
}
/*
* Now zap any remaining smgr cache entries. This must happen before we
* start to rebuild entries, since that may involve catalog fetches which
* will re-open catalog files.
*/
smgrcloseall();
/* Phase 2: rebuild the items found to need rebuild in phase 1 */
foreach(l, rebuildFirstList)
{ relation = (Relation) lfirst(l);
RelationClearRelation(relation, true);
}
list_free(rebuildFirstList);
foreach(l, rebuildList)
{
relation = (Relation) lfirst(l);
RelationClearRelation(relation, true);
}
list_free(rebuildList);
}
/*
* AtEOXact_RelationCache
*
* Clean up the relcache at main-transaction commit or abort.
*
* Note: this must be called *before* processing invalidation messages.
* In the case of abort, we don't want to try to rebuild any invalidated
* cache entries (since we can't safely do database accesses). Therefore
* we must reset refcnts before handling pending invalidations.
*
* As of PostgreSQL 8.1, relcache refcnts should get released by the
* ResourceOwner mechanism. This routine just does a debugging
* cross-check that no pins remain. However, we also need to do special
* cleanup when the current transaction created any relations or made use
* of forced index lists.
*/
void
AtEOXact_RelationCache(bool isCommit)
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
/*
* To speed up transaction exit, we want to avoid scanning the relcache
* unless there is actually something for this routine to do. Other than
* the debug-only Assert checks, most transactions don't create any work
* for us to do here, so we keep a static flag that gets set if there is
* anything to do. (Currently, this means either a relation is created in
* the current xact, or one is given a new relfilenode, or an index list
* is forced.) For simplicity, the flag remains set till end of top-level
* transaction, even though we could clear it at subtransaction end in
* some cases.
*/
if (!need_eoxact_work
#ifdef USE_ASSERT_CHECKING
&& !assert_enabled
#endif
)
return;
hash_seq_init(&status, RelationIdCache);
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
Relation relation = idhentry->reldesc;
/*
* The relcache entry's ref count should be back to its normal
* not-in-a-transaction state: 0 unless it's nailed in cache.
*
* In bootstrap mode, this is NOT true, so don't check it --- the
* bootstrap code expects relations to stay open across start/commit
* transaction calls. (That seems bogus, but it's not worth fixing.)
*/
#ifdef USE_ASSERT_CHECKING
if (!IsBootstrapProcessingMode())
{
int expected_refcnt;
expected_refcnt = relation->rd_isnailed ? 1 : 0;
Assert(relation->rd_refcnt == expected_refcnt);
}
#endif
/*
* Is it a relation created in the current transaction?
*
* During commit, reset the flag to zero, since we are now out of the
* creating transaction. During abort, simply delete the relcache
* entry --- it isn't interesting any longer. (NOTE: if we have
* forgotten the new-ness of a new relation due to a forced cache
* flush, the entry will get deleted anyway by shared-cache-inval
* processing of the aborted pg_class insertion.)
*/
if (relation->rd_createSubid != InvalidSubTransactionId)
{
if (isCommit)
relation->rd_createSubid = InvalidSubTransactionId;
else
{
RelationClearRelation(relation, false);
continue;
}
}
/*
* Likewise, reset the hint about the relfilenode being new.
*/
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
/*
* Flush any temporary index list.
*/
if (relation->rd_indexvalid == 2)
{
list_free(relation->rd_indexlist);
relation->rd_indexlist = NIL;
relation->rd_oidindex = InvalidOid;
relation->rd_indexvalid = 0;
}
}
/* Once done with the transaction, we can reset need_eoxact_work */
need_eoxact_work = false;
}
/*
* AtEOSubXact_RelationCache
*
* Clean up the relcache at sub-transaction commit or abort.
*
* Note: this must be called *before* processing invalidation messages.
*/
void
AtEOSubXact_RelationCache(bool isCommit, SubTransactionId mySubid,
SubTransactionId parentSubid)
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
/*
* Skip the relcache scan if nothing to do --- see notes for
* AtEOXact_RelationCache.
*/
if (!need_eoxact_work)
return;
hash_seq_init(&status, RelationIdCache);
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
Relation relation = idhentry->reldesc;
/*
* Is it a relation created in the current subtransaction?
*
* During subcommit, mark it as belonging to the parent, instead.
* During subabort, simply delete the relcache entry.
*/
if (relation->rd_createSubid == mySubid)
{
if (isCommit)
relation->rd_createSubid = parentSubid;
else
{
Assert(RelationHasReferenceCountZero(relation));
RelationClearRelation(relation, false);
continue;
}
}
/*
* Likewise, update or drop any new-relfilenode-in-subtransaction hint.
*/
if (relation->rd_newRelfilenodeSubid == mySubid)
{
if (isCommit)
relation->rd_newRelfilenodeSubid = parentSubid;
else
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
}
/*
* Flush any temporary index list.
*/
if (relation->rd_indexvalid == 2)
{
list_free(relation->rd_indexlist);
relation->rd_indexlist = NIL;
relation->rd_oidindex = InvalidOid;
relation->rd_indexvalid = 0;
}
}
}
/*
* RelationCacheMarkNewRelfilenode
*
* Mark the rel as having been given a new relfilenode in the current
* (sub) transaction. This is a hint that can be used to optimize
* later operations on the rel in the same transaction.
*/
void
RelationCacheMarkNewRelfilenode(Relation rel)
{
/* Mark it... */
rel->rd_newRelfilenodeSubid = GetCurrentSubTransactionId();
/* ... and now we have eoxact cleanup work to do */
need_eoxact_work = true;
}
/*
* RelationBuildLocalRelation
* Build a relcache entry for an about-to-be-created relation,
* and enter it into the relcache.
*/
RelationRelationBuildLocalRelation(const char *relname,
Oid relnamespace,
TupleDesc tupDesc,
Oid relid,
Oid reltablespace,
bool shared_relation)
{
Relation rel;
MemoryContext oldcxt;
int natts = tupDesc->natts;
int i;
bool has_not_null;
bool nailit;
AssertArg(natts >= 0);
/*
* check for creation of a rel that must be nailed in cache.
*
* XXX this list had better match RelationCacheInitializePhase2's list.
*/
switch (relid)
{
case RelationRelationId:
case AttributeRelationId:
case ProcedureRelationId:
case TypeRelationId:
nailit = true;
break;
default:
nailit = false;
break;
}
/*
* check that hardwired list of shared rels matches what's in the
* bootstrap .bki file. If you get a failure here during initdb, you
* probably need to fix IsSharedRelation() to match whatever you've done
* to the set of shared relations.
*/
if (shared_relation != IsSharedRelation(relid))
elog(ERROR, "shared_relation flag for \"%s\" does not match IsSharedRelation(%u)",
relname, relid);
/*
* switch to the cache context to create the relcache entry.
*/
if (!CacheMemoryContext)
CreateCacheMemoryContext();
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
/*
* allocate a new relation descriptor and fill in basic state fields.
*/
rel = (Relation) palloc0(sizeof(RelationData));
rel->rd_targblock = InvalidBlockNumber;
/* make sure relation is marked as having no open file yet */
rel->rd_smgr = NULL;
/* mark it nailed if appropriate */
rel->rd_isnailed = nailit;
rel->rd_refcnt = nailit ? 1 : 0;
/* it's being created in this transaction */
rel->rd_createSubid = GetCurrentSubTransactionId();
rel->rd_newRelfilenodeSubid = InvalidSubTransactionId;
/* must flag that we have rels created in this transaction */
need_eoxact_work = true;
/* is it a temporary relation? */
rel->rd_istemp = isTempNamespace(relnamespace);
/*
* create a new tuple descriptor from the one passed in. We do this
* partly to copy it into the cache context, and partly because the new
* relation can't have any defaults or constraints yet; they have to be
* added in later steps, because they require additions to multiple system
* catalogs. We can copy attnotnull constraints here, however.
*/
rel->rd_att = CreateTupleDescCopy(tupDesc);
rel->rd_att->tdrefcount = 1; /* mark as refcounted */
has_not_null = false;
for (i = 0; i < natts; i++)
{
rel->rd_att->attrs[i]->attnotnull = tupDesc->attrs[i]->attnotnull;
has_not_null |= tupDesc->attrs[i]->attnotnull;
}
if (has_not_null)
{
TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
constr->has_not_null = true;
rel->rd_att->constr = constr;
}
/*
* initialize relation tuple form (caller may add/override data later)
*/
rel->rd_rel = (Form_pg_class) palloc0(CLASS_TUPLE_SIZE);
namestrcpy(&rel->rd_rel->relname, relname);
rel->rd_rel->relnamespace = relnamespace;
rel->rd_rel->relkind = RELKIND_UNCATALOGED;
rel->rd_rel->relhasoids = rel->rd_att->tdhasoid;
rel->rd_rel->relnatts = natts;
rel->rd_rel->reltype = InvalidOid;
/* needed when bootstrapping: */
rel->rd_rel->relowner = BOOTSTRAP_SUPERUSERID;
/*
* Insert relation physical and logical identifiers (OIDs) into the right
* places. Note that the physical ID (relfilenode) is initially the same
* as the logical ID (OID).
*/
rel->rd_rel->relisshared = shared_relation;
RelationGetRelid(rel) = relid;
for (i = 0; i < natts; i++)
rel->rd_att->attrs[i]->attrelid = relid;
rel->rd_rel->relfilenode = relid;
rel->rd_rel->reltablespace = reltablespace;
RelationInitLockInfo(rel); /* see lmgr.c */
RelationInitPhysicalAddr(rel);
/*
* Okay to insert into the relcache hash tables.
*/
RelationCacheInsert(rel);
/*
* done building relcache entry.
*/
MemoryContextSwitchTo(oldcxt);
/* It's fully valid */
rel->rd_isvalid = true;
/*
* Caller expects us to pin the returned entry.
*/
RelationIncrementReferenceCount(rel);
return rel;
}
/*
* RelationCacheInitialize
*
* This initializes the relation descriptor cache. At the time
* that this is invoked, we can't do database access yet (mainly
* because the transaction subsystem is not up); all we are doing
* is making an empty cache hashtable. This must be done before
* starting the initialization transaction, because otherwise
* AtEOXact_RelationCache would crash if that transaction aborts
* before we can get the relcache set up.
*/
#define INITRELCACHESIZE 400
void
RelationCacheInitialize(void)
{
MemoryContext oldcxt;
HASHCTL ctl;
/*
* switch to cache memory context
*/
if (!CacheMemoryContext)
CreateCacheMemoryContext();
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
/*
* create hashtable that indexes the relcache
*/
MemSet(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(Oid);
ctl.entrysize = sizeof(RelIdCacheEnt);
ctl.hash = oid_hash;
RelationIdCache = hash_create("Relcache by OID", INITRELCACHESIZE,
&ctl, HASH_ELEM | HASH_FUNCTION);
MemoryContextSwitchTo(oldcxt);
}
/*
* RelationCacheInitializePhase2
*
* This is called as soon as the catcache and transaction system
* are functional. At this point we can actually read data from
* the system catalogs. We first try to read pre-computed relcache
* entries from the pg_internal.init file. If that's missing or
* broken, make phony entries for the minimum set of nailed-in-cache
* relations. Then (unless bootstrapping) make sure we have entries
* for the critical system indexes. Once we've done all this, we
* have enough infrastructure to open any system catalog or use any
* catcache. The last step is to rewrite pg_internal.init if needed.
*/void
RelationCacheInitializePhase2(void)
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
MemoryContext oldcxt;
bool needNewCacheFile = false;
/*
* switch to cache memory context
*/
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
/*
* Try to load the relcache cache file. If unsuccessful, bootstrap the
* cache with pre-made descriptors for the critical "nailed-in" system
* catalogs.
*/
if (IsBootstrapProcessingMode() ||
!load_relcache_init_file())
{
needNewCacheFile = true;
formrdesc("pg_class", PG_CLASS_RELTYPE_OID,
true, Natts_pg_class, Desc_pg_class);
formrdesc("pg_attribute", PG_ATTRIBUTE_RELTYPE_OID,
false, Natts_pg_attribute, Desc_pg_attribute);
formrdesc("pg_proc", PG_PROC_RELTYPE_OID,
true, Natts_pg_proc, Desc_pg_proc);
formrdesc("pg_type", PG_TYPE_RELTYPE_OID,
true, Natts_pg_type, Desc_pg_type);
#define NUM_CRITICAL_RELS 4 /* fix if you change list above */
}
MemoryContextSwitchTo(oldcxt);
/* In bootstrap mode, the faked-up formrdesc info is all we'll have */
if (IsBootstrapProcessingMode())
return;
/*
* If we didn't get the critical system indexes loaded into relcache, do
* so now. These are critical because the catcache and/or opclass cache
* depend on them for fetches done during relcache load. Thus, we have an
* infinite-recursion problem. We can break the recursion by doing
* heapscans instead of indexscans at certain key spots. To avoid hobbling
* performance, we only want to do that until we have the critical indexes
* loaded into relcache. Thus, the flag criticalRelcachesBuilt is used to
* decide whether to do heapscan or indexscan at the key spots, and we set
* it true after we've loaded the critical indexes.
*
* The critical indexes are marked as "nailed in cache", partly to make it
* easy for load_relcache_init_file to count them, but mainly because we
* cannot flush and rebuild them once we've set criticalRelcachesBuilt to
* true. (NOTE: perhaps it would be possible to reload them by
* temporarily setting criticalRelcachesBuilt to false again. For now,
* though, we just nail 'em in.)
*
* RewriteRelRulenameIndexId and TriggerRelidNameIndexId are not critical
* in the same way as the others, because the critical catalogs don't
* (currently) have any rules or triggers, and so these indexes can be
* rebuilt without inducing recursion. However they are used during
* relcache load when a rel does have rules or triggers, so we choose to
* nail them for performance reasons.
*/
if (!criticalRelcachesBuilt)
{
Relation ird;
#define LOAD_CRIT_INDEX(indexoid) \
do { \
ird = RelationBuildDesc((indexoid), NULL); \
ird->rd_isnailed = true; \
ird->rd_refcnt = 1; \
} while (0)
LOAD_CRIT_INDEX(ClassOidIndexId);
LOAD_CRIT_INDEX(AttributeRelidNumIndexId);
LOAD_CRIT_INDEX(IndexRelidIndexId);
LOAD_CRIT_INDEX(OpclassOidIndexId);
LOAD_CRIT_INDEX(AccessMethodStrategyIndexId);
LOAD_CRIT_INDEX(AccessMethodProcedureIndexId);
LOAD_CRIT_INDEX(OperatorOidIndexId);
LOAD_CRIT_INDEX(RewriteRelRulenameIndexId);
LOAD_CRIT_INDEX(TriggerRelidNameIndexId);
#define NUM_CRITICAL_INDEXES 9 /* fix if you change list above */
criticalRelcachesBuilt = true;
}
/*
* Now, scan all the relcache entries and update anything that might be
* wrong in the results from formrdesc or the relcache cache file. If we
* faked up relcache entries using formrdesc, then read the real pg_class
* rows and replace the fake entries with them. Also, if any of the
* relcache entries have rules or triggers, load that info the hard way
* since it isn't recorded in the cache file.
*/
hash_seq_init(&status, RelationIdCache);
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
Relation relation = idhentry->reldesc;
/*
* If it's a faked-up entry, read the real pg_class tuple.
*/
if (needNewCacheFile && relation->rd_isnailed)
{
HeapTuple htup;
Form_pg_class relp;
htup = SearchSysCache(RELOID,
ObjectIdGetDatum(RelationGetRelid(relation)),
0, 0, 0);
if (!HeapTupleIsValid(htup))
elog(FATAL, "cache lookup failed for relation %u",
RelationGetRelid(relation));
relp = (Form_pg_class) GETSTRUCT(htup);
/*
* Copy tuple to relation->rd_rel. (See notes in
* AllocateRelationDesc())
*/
Assert(relation->rd_rel != NULL);
memcpy((char *) relation->rd_rel, (char *) relp, CLASS_TUPLE_SIZE);
/* Update rd_options while we have the tuple */
if (relation->rd_options)
pfree(relation->rd_options);
RelationParseRelOptions(relation, htup);
/*
* Also update the derived fields in rd_att.
*/
relation->rd_att->tdtypeid = relp->reltype;
relation->rd_att->tdtypmod = -1; /* unnecessary, but... */
relation->rd_att->tdhasoid = relp->relhasoids;
ReleaseSysCache(htup);
}
/*
* Fix data that isn't saved in relcache cache file.
*/
if (relation->rd_rel->relhasrules && relation->rd_rules == NULL)
RelationBuildRuleLock(relation);
if (relation->rd_rel->reltriggers > 0 && relation->trigdesc == NULL)
RelationBuildTriggers(relation);
}
/*
* Lastly, write out a new relcache cache file if one is needed.
*/
if (needNewCacheFile)
{
/*
* Force all the catcaches to finish initializing and thereby open the
* catalogs and indexes they use. This will preload the relcache with
* entries for all the most important system catalogs and indexes, so
* that the init file will be most useful for future backends.
*/
InitCatalogCachePhase2();
/* now write the file */
write_relcache_init_file();
}
}
/*
* GetPgClassDescriptor -- get a predefined tuple descriptor for pg_class
* GetPgIndexDescriptor -- get a predefined tuple descriptor for pg_index
*
* We need this kluge because we have to be able to access non-fixed-width
* fields of pg_class and pg_index before we have the standard catalog caches
* available. We use predefined data that's set up in just the same way as
* the bootstrapped reldescs used by formrdesc(). The resulting tupdesc is
* not 100% kosher: it does not have the correct rowtype OID in tdtypeid, nor
* does it have a TupleConstr field. But it's good enough for the purpose of
* extracting fields.
*/
static TupleDesc
BuildHardcodedDescriptor(int natts, Form_pg_attribute attrs, bool hasoids)
{
TupleDesc result;
MemoryContext oldcxt;
int i;
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
result = CreateTemplateTupleDesc(natts, hasoids);
result->tdtypeid = RECORDOID; /* not right, but we don't care */
result->tdtypmod = -1;
for (i = 0; i < natts; i++)
{
memcpy(result->attrs[i], &attrs[i], ATTRIBUTE_TUPLE_SIZE);
/* make sure attcacheoff is valid */
result->attrs[i]->attcacheoff = -1;
}
/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
result->attrs[0]->attcacheoff = 0;
/* Note: we don't bother to set up a TupleConstr entry */
MemoryContextSwitchTo(oldcxt);
return result;
}
static TupleDesc
GetPgClassDescriptor(void)
{
static TupleDesc pgclassdesc = NULL;
/* Already done? */
if (pgclassdesc == NULL)
pgclassdesc = BuildHardcodedDescriptor(Natts_pg_class,
Desc_pg_class,
true);
return pgclassdesc;
}
static TupleDesc
GetPgIndexDescriptor(void)
{
static TupleDesc pgindexdesc = NULL;
/* Already done? */
if (pgindexdesc == NULL)
pgindexdesc = BuildHardcodedDescriptor(Natts_pg_index,
Desc_pg_index,
false);
return pgindexdesc;
}
static void
AttrDefaultFetch(Relation relation)
{
AttrDefault *attrdef = relation->rd_att->constr->defval;
int ndef = relation->rd_att->constr->num_defval;
Relation adrel;
SysScanDesc adscan;
ScanKeyData skey;
HeapTuple htup;
Datum val;
bool isnull;
int found;
int i;
ScanKeyInit(&skey,
Anum_pg_attrdef_adrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
adrel = heap_open(AttrDefaultRelationId, AccessShareLock);
adscan = systable_beginscan(adrel, AttrDefaultIndexId, true,
SnapshotNow, 1, &skey);
found = 0;
while (HeapTupleIsValid(htup = systable_getnext(adscan)))
{
Form_pg_attrdef adform = (Form_pg_attrdef) GETSTRUCT(htup);
for (i = 0; i < ndef; i++)
{
if (adform->adnum != attrdef[i].adnum)
continue;
if (attrdef[i].adbin != NULL)
elog(WARNING, "multiple attrdef records found for attr %s of rel %s",
NameStr(relation->rd_att->attrs[adform->adnum - 1]->attname),
RelationGetRelationName(relation));
else
found++;
val = fastgetattr(htup,
Anum_pg_attrdef_adbin,
adrel->rd_att, &isnull);
if (isnull)
elog(WARNING, "null adbin for attr %s of rel %s",
NameStr(relation->rd_att->attrs[adform->adnum - 1]->attname),
RelationGetRelationName(relation));
else
attrdef[i].adbin = MemoryContextStrdup(CacheMemoryContext,
DatumGetCString(DirectFunctionCall1(textout,
val)));
break;
}
if (i >= ndef)
elog(WARNING, "unexpected attrdef record found for attr %d of rel %s",
adform->adnum, RelationGetRelationName(relation));
}
systable_endscan(adscan);
heap_close(adrel, AccessShareLock);
if (found != ndef)
elog(WARNING, "%d attrdef record(s) missing for rel %s",
ndef - found, RelationGetRelationName(relation));
}
static void
CheckConstraintFetch(Relation relation)
{
ConstrCheck *check = relation->rd_att->constr->check;
int ncheck = relation->rd_att->constr->num_check;
Relation conrel;
SysScanDesc conscan;
ScanKeyData skey[1];
HeapTuple htup;
Datum val;
bool isnull;
int found = 0;
ScanKeyInit(&skey[0],
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
conrel = heap_open(ConstraintRelationId, AccessShareLock);
conscan = systable_beginscan(conrel, ConstraintRelidIndexId, true,
SnapshotNow, 1, skey);
while (HeapTupleIsValid(htup = systable_getnext(conscan)))
{
Form_pg_constraint conform = (Form_pg_constraint) GETSTRUCT(htup);
/* We want check constraints only */
if (conform->contype != CONSTRAINT_CHECK)
continue;
if (found >= ncheck)
elog(ERROR, "unexpected constraint record found for rel %s",
RelationGetRelationName(relation));
check[found].ccname = MemoryContextStrdup(CacheMemoryContext,
NameStr(conform->conname));
/* Grab and test conbin is actually set */
val = fastgetattr(htup,
Anum_pg_constraint_conbin,
conrel->rd_att, &isnull);
if (isnull)
elog(ERROR, "null conbin for rel %s", RelationGetRelationName(relation));
check[found].ccbin = MemoryContextStrdup(CacheMemoryContext,
DatumGetCString(DirectFunctionCall1(textout,
val)));
found++;
}
systable_endscan(conscan);
heap_close(conrel, AccessShareLock);
if (found != ncheck)
elog(ERROR, "%d constraint record(s) missing for rel %s",
ncheck - found, RelationGetRelationName(relation));
}
/*
* RelationGetIndexList -- get a list of OIDs of indexes on this relation
*
* The index list is created only if someone requests it. We scan pg_index
* to find relevant indexes, and add the list to the relcache entry so that
* we won't have to compute it again. Note that shared cache inval of a
* relcache entry will delete the old list and set rd_indexvalid to 0,
* so that we must recompute the index list on next request. This handles
* creation or deletion of an index.
*
* The returned list is guaranteed to be sorted in order by OID. This is
* needed by the executor, since for index types that we obtain exclusive
* locks on when updating the index, all backends must lock the indexes in
* the same order or we will get deadlocks (see ExecOpenIndices()). Any
* consistent ordering would do, but ordering by OID is easy.
*
* Since shared cache inval causes the relcache's copy of the list to go away,
* we return a copy of the list palloc'd in the caller's context. The caller
* may list_free() the returned list after scanning it. This is necessary
* since the caller will typically be doing syscache lookups on the relevant
* indexes, and syscache lookup could cause SI messages to be processed!
*
* We also update rd_oidindex, which this module treats as effectively part
* of the index list. rd_oidindex is valid when rd_indexvalid isn't zero;
* it is the pg_class OID of a unique index on OID when the relation has one,
* and InvalidOid if there is no such index.
*/
List *
RelationGetIndexList(Relation relation)
{
Relation indrel;
SysScanDesc indscan;
ScanKeyData skey;
HeapTuple htup;
List *result;
Oid oidIndex;
MemoryContext oldcxt;
/* Quick exit if we already computed the list. */
if (relation->rd_indexvalid != 0)
return list_copy(relation->rd_indexlist);
/*
* We build the list we intend to return (in the caller's context) while
* doing the scan. After successfully completing the scan, we copy that
* list into the relcache entry. This avoids cache-context memory leakage
* if we get some sort of error partway through.
*/
result = NIL;
oidIndex = InvalidOid;
/* Prepare to scan pg_index for entries having indrelid = this rel. */
ScanKeyInit(&skey,
Anum_pg_index_indrelid, BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
indrel = heap_open(IndexRelationId, AccessShareLock);
indscan = systable_beginscan(indrel, IndexIndrelidIndexId, true,
SnapshotNow, 1, &skey);
while (HeapTupleIsValid(htup = systable_getnext(indscan)))
{
Form_pg_index index = (Form_pg_index) GETSTRUCT(htup);
/* Add index's OID to result list in the proper order */
result = insert_ordered_oid(result, index->indexrelid);
/* Check to see if it is a unique, non-partial btree index on OID */
if (index->indnatts == 1 &&
index->indisunique &&
index->indkey.values[0] == ObjectIdAttributeNumber &&
index->indclass.values[0] == OID_BTREE_OPS_OID &&
heap_attisnull(htup, Anum_pg_index_indpred))
oidIndex = index->indexrelid;
}
systable_endscan(indscan);
heap_close(indrel, AccessShareLock);
/* Now save a copy of the completed list in the relcache entry. */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
relation->rd_indexlist = list_copy(result);
relation->rd_oidindex = oidIndex;
relation->rd_indexvalid = 1;
MemoryContextSwitchTo(oldcxt);
return result;
}
/*
* insert_ordered_oid
* Insert a new Oid into a sorted list of Oids, preserving ordering
*
* Building the ordered list this way is O(N^2), but with a pretty small
* constant, so for the number of entries we expect it will probably be
* faster than trying to apply qsort(). Most tables don't have very many
* indexes...
*/
static List *
insert_ordered_oid(List *list, Oid datum)
{
ListCell *prev;
/* Does the datum belong at the front? */
if (list == NIL || datum < linitial_oid(list))
return lcons_oid(datum, list);
/* No, so find the entry it belongs after */
prev = list_head(list);
for (;;)
{
ListCell *curr = lnext(prev);
if (curr == NULL || datum < lfirst_oid(curr))
break; /* it belongs after 'prev', before 'curr' */
prev = curr;
}
/* Insert datum into list after 'prev' */
lappend_cell_oid(list, prev, datum);
return list;
}
/* * RelationSetIndexList -- externally force the index list contents
*
* This is used to temporarily override what we think the set of valid
* indexes is (including the presence or absence of an OID index).
* The forcing will be valid only until transaction commit or abort.
*
* This should only be applied to nailed relations, because in a non-nailed
* relation the hacked index list could be lost at any time due to SI
* messages. In practice it is only used on pg_class (see REINDEX).
*
* It is up to the caller to make sure the given list is correctly ordered.
*/
void
RelationSetIndexList(Relation relation, List *indexIds, Oid oidIndex)
{
MemoryContext oldcxt;
Assert(relation->rd_isnailed);
/* Copy the list into the cache context (could fail for lack of mem) */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
indexIds = list_copy(indexIds);
MemoryContextSwitchTo(oldcxt);
/* Okay to replace old list */
list_free(relation->rd_indexlist);
relation->rd_indexlist = indexIds;
relation->rd_oidindex = oidIndex;
relation->rd_indexvalid = 2; /* mark list as forced */
/* must flag that we have a forced index list */
need_eoxact_work = true;
}
/*
* RelationGetOidIndex -- get the pg_class OID of the relation's OID index
*
* Returns InvalidOid if there is no such index.
*/
Oid
RelationGetOidIndex(Relation relation)
{
List *ilist;
/*
* If relation doesn't have OIDs at all, caller is probably confused. (We
* could just silently return InvalidOid, but it seems better to throw an
* assertion.)
*/
Assert(relation->rd_rel->relhasoids);
if (relation->rd_indexvalid == 0)
{
/* RelationGetIndexList does the heavy lifting. */
ilist = RelationGetIndexList(relation);
list_free(ilist);
Assert(relation->rd_indexvalid != 0);
}
return relation->rd_oidindex;
}
/*
* RelationGetIndexExpressions -- get the index expressions for an index
*
* We cache the result of transforming pg_index.indexprs into a node tree.
* If the rel is not an index or has no expressional columns, we return NIL.
* Otherwise, the returned tree is copied into the caller's memory context.
* (We don't want to return a pointer to the relcache copy, since it could
* disappear due to relcache invalidation.)
*/
List *
RelationGetIndexExpressions(Relation relation){
List *result;
Datum exprsDatum;
bool isnull;
char *exprsString;
MemoryContext oldcxt;
/* Quick exit if we already computed the result. */
if (relation->rd_indexprs)
return (List *) copyObject(relation->rd_indexprs);
/* Quick exit if there is nothing to do. */
if (relation->rd_indextuple == NULL ||
heap_attisnull(relation->rd_indextuple, Anum_pg_index_indexprs))
return NIL;
/*
* We build the tree we intend to return in the caller's context. After
* successfully completing the work, we copy it into the relcache entry.
* This avoids problems if we get some sort of error partway through.
*/
exprsDatum = heap_getattr(relation->rd_indextuple,
Anum_pg_index_indexprs,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
exprsString = DatumGetCString(DirectFunctionCall1(textout, exprsDatum));
result = (List *) stringToNode(exprsString);
pfree(exprsString);
/*
* Run the expressions through eval_const_expressions. This is not just an
* optimization, but is necessary, because the planner will be comparing
* them to similarly-processed qual clauses, and may fail to detect valid
* matches without this. We don't bother with canonicalize_qual, however.
*/
result = (List *) eval_const_expressions((Node *) result);
/*
* Also mark any coercion format fields as "don't care", so that the
* planner can match to both explicit and implicit coercions.
*/
set_coercionform_dontcare((Node *) result);
/* May as well fix opfuncids too */
fix_opfuncids((Node *) result);
/* Now save a copy of the completed tree in the relcache entry. */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
relation->rd_indexprs = (List *) copyObject(result);
MemoryContextSwitchTo(oldcxt);
return result;
}
/*
* RelationGetIndexPredicate -- get the index predicate for an index
*
* We cache the result of transforming pg_index.indpred into an implicit-AND
* node tree (suitable for ExecQual).
* If the rel is not an index or has no predicate, we return NIL.
* Otherwise, the returned tree is copied into the caller's memory context.
* (We don't want to return a pointer to the relcache copy, since it could
* disappear due to relcache invalidation.)
*/
List *
RelationGetIndexPredicate(Relation relation)
{
List *result;
Datum predDatum; bool isnull;
char *predString;
MemoryContext oldcxt;
/* Quick exit if we already computed the result. */
if (relation->rd_indpred)
return (List *) copyObject(relation->rd_indpred);
/* Quick exit if there is nothing to do. */
if (relation->rd_indextuple == NULL ||
heap_attisnull(relation->rd_indextuple, Anum_pg_index_indpred))
return NIL;
/*
* We build the tree we intend to return in the caller's context. After
* successfully completing the work, we copy it into the relcache entry.
* This avoids problems if we get some sort of error partway through.
*/
predDatum = heap_getattr(relation->rd_indextuple,
Anum_pg_index_indpred,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
predString = DatumGetCString(DirectFunctionCall1(textout, predDatum));
result = (List *) stringToNode(predString);
pfree(predString);
/*
* Run the expression through const-simplification and canonicalization.
* This is not just an optimization, but is necessary, because the planner
* will be comparing it to similarly-processed qual clauses, and may fail
* to detect valid matches without this. This must match the processing
* done to qual clauses in preprocess_expression()! (We can skip the
* stuff involving subqueries, however, since we don't allow any in index
* predicates.)
*/
result = (List *) eval_const_expressions((Node *) result);
result = (List *) canonicalize_qual((Expr *) result);
/*
* Also mark any coercion format fields as "don't care", so that the
* planner can match to both explicit and implicit coercions.
*/
set_coercionform_dontcare((Node *) result);
/* Also convert to implicit-AND format */
result = make_ands_implicit((Expr *) result);
/* May as well fix opfuncids too */
fix_opfuncids((Node *) result);
/* Now save a copy of the completed tree in the relcache entry. */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
relation->rd_indpred = (List *) copyObject(result);
MemoryContextSwitchTo(oldcxt);
return result;
}
/*
* load_relcache_init_file, write_relcache_init_file
*
* In late 1992, we started regularly having databases with more than
* a thousand classes in them. With this number of classes, it became
* critical to do indexed lookups on the system catalogs.
*
* Bootstrapping these lookups is very hard. We want to be able to
* use an index on pg_attribute, for example, but in order to do so, * we must have read pg_attribute for the attributes in the index,
* which implies that we need to use the index.
*
* In order to get around the problem, we do the following:
*
* + When the database system is initialized (at initdb time), we
* don't use indexes. We do sequential scans.
*
* + When the backend is started up in normal mode, we load an image
* of the appropriate relation descriptors, in internal format,
* from an initialization file in the data/base/... directory.
*
* + If the initialization file isn't there, then we create the
* relation descriptors using sequential scans and write 'em to
* the initialization file for use by subsequent backends.
*
* We could dispense with the initialization file and just build the
* critical reldescs the hard way on every backend startup, but that
* slows down backend startup noticeably.
*
* We can in fact go further, and save more relcache entries than
* just the ones that are absolutely critical; this allows us to speed
* up backend startup by not having to build such entries the hard way.
* Presently, all the catalog and index entries that are referred to
* by catcaches are stored in the initialization file.
*
* The same mechanism that detects when catcache and relcache entries
* need to be invalidated (due to catalog updates) also arranges to
* unlink the initialization file when its contents may be out of date.
* The file will then be rebuilt during the next backend startup.
*/
/*
* load_relcache_init_file -- attempt to load cache from the init file
*
* If successful, return TRUE and set criticalRelcachesBuilt to true.
* If not successful, return FALSE.
*
* NOTE: we assume we are already switched into CacheMemoryContext.
*/
static bool
load_relcache_init_file(void)
{
FILE *fp;
char initfilename[MAXPGPATH];
Relation *rels;
int relno,
num_rels,
max_rels,
nailed_rels,
nailed_indexes,
magic;
int i;
snprintf(initfilename, sizeof(initfilename), "%s/%s",
DatabasePath, RELCACHE_INIT_FILENAME);
fp = AllocateFile(initfilename, PG_BINARY_R);
if (fp == NULL)
return false;
/*
* Read the index relcache entries from the file. Note we will not enter
* any of them into the cache if the read fails partway through; this
* helps to guard against broken init files.
*/
max_rels = 100;
rels = (Relation *) palloc(max_rels * sizeof(Relation));
num_rels = 0;
nailed_rels = nailed_indexes = 0; initFileRelationIds = NIL;
/* check for correct magic number (compatible version) */
if (fread(&magic, 1, sizeof(magic), fp) != sizeof(magic))
goto read_failed;
if (magic != RELCACHE_INIT_FILEMAGIC)
goto read_failed;
for (relno = 0;; relno++)
{
Size len;
size_t nread;
Relation rel;
Form_pg_class relform;
bool has_not_null;
/* first read the relation descriptor length */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
{
if (nread == 0)
break; /* end of file */
goto read_failed;
}
/* safety check for incompatible relcache layout */
if (len != sizeof(RelationData))
goto read_failed;
/* allocate another relcache header */
if (num_rels >= max_rels)
{
max_rels *= 2;
rels = (Relation *) repalloc(rels, max_rels * sizeof(Relation));
}
rel = rels[num_rels++] = (Relation) palloc(len);
/* then, read the Relation structure */
if ((nread = fread(rel, 1, len, fp)) != len)
goto read_failed;
/* next read the relation tuple form */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
relform = (Form_pg_class) palloc(len);
if ((nread = fread(relform, 1, len, fp)) != len)
goto read_failed;
rel->rd_rel = relform;
/* initialize attribute tuple forms */
rel->rd_att = CreateTemplateTupleDesc(relform->relnatts,
relform->relhasoids);
rel->rd_att->tdrefcount = 1; /* mark as refcounted */
rel->rd_att->tdtypeid = relform->reltype;
rel->rd_att->tdtypmod = -1; /* unnecessary, but... */
/* next read all the attribute tuple form data entries */
has_not_null = false;
for (i = 0; i < relform->relnatts; i++)
{
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
if (len != ATTRIBUTE_TUPLE_SIZE)
goto read_failed;
if ((nread = fread(rel->rd_att->attrs[i], 1, len, fp)) != len)
goto read_failed;
has_not_null |= rel->rd_att->attrs[i]->attnotnull;
}
/* next read the access method specific field */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
if (len > 0)
{
rel->rd_options = palloc(len);
if ((nread = fread(rel->rd_options, 1, len, fp)) != len)
goto read_failed;
if (len != VARSIZE(rel->rd_options))
goto read_failed; /* sanity check */
}
else
{
rel->rd_options = NULL;
}
/* mark not-null status */
if (has_not_null)
{
TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
constr->has_not_null = true;
rel->rd_att->constr = constr;
}
/* If it's an index, there's more to do */
if (rel->rd_rel->relkind == RELKIND_INDEX)
{
Form_pg_am am;
MemoryContext indexcxt;
Oid *opfamily;
Oid *opcintype;
Oid *operator;
RegProcedure *support;
int nsupport;
int16 *indoption;
/* Count nailed indexes to ensure we have 'em all */
if (rel->rd_isnailed)
nailed_indexes++;
/* next, read the pg_index tuple */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
rel->rd_indextuple = (HeapTuple) palloc(len);
if ((nread = fread(rel->rd_indextuple, 1, len, fp)) != len)
goto read_failed;
/* Fix up internal pointers in the tuple -- see heap_copytuple */
rel->rd_indextuple->t_data = (HeapTupleHeader) ((char *) rel->rd_indextuple + HEAPTUPLESIZE);
rel->rd_index = (Form_pg_index) GETSTRUCT(rel->rd_indextuple);
/* next, read the access method tuple form */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
am = (Form_pg_am) palloc(len);
if ((nread = fread(am, 1, len, fp)) != len)
goto read_failed;
rel->rd_am = am;
/*
* prepare index info context --- parameters should match
* RelationInitIndexAccessInfo
*/
indexcxt = AllocSetContextCreate(CacheMemoryContext, RelationGetRelationName(rel),
ALLOCSET_SMALL_MINSIZE,
ALLOCSET_SMALL_INITSIZE,
ALLOCSET_SMALL_MAXSIZE);
rel->rd_indexcxt = indexcxt;
/* next, read the vector of opfamily OIDs */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
opfamily = (Oid *) MemoryContextAlloc(indexcxt, len);
if ((nread = fread(opfamily, 1, len, fp)) != len)
goto read_failed;
rel->rd_opfamily = opfamily;
/* next, read the vector of opcintype OIDs */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
opcintype = (Oid *) MemoryContextAlloc(indexcxt, len);
if ((nread = fread(opcintype, 1, len, fp)) != len)
goto read_failed;
rel->rd_opcintype = opcintype;
/* next, read the vector of operator OIDs */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
operator = (Oid *) MemoryContextAlloc(indexcxt, len);
if ((nread = fread(operator, 1, len, fp)) != len)
goto read_failed;
rel->rd_operator = operator;
/* next, read the vector of support procedures */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
support = (RegProcedure *) MemoryContextAlloc(indexcxt, len);
if ((nread = fread(support, 1, len, fp)) != len)
goto read_failed;
rel->rd_support = support;
/* finally, read the vector of indoption values */
if ((nread = fread(&len, 1, sizeof(len), fp)) != sizeof(len))
goto read_failed;
indoption = (int16 *) MemoryContextAlloc(indexcxt, len);
if ((nread = fread(indoption, 1, len, fp)) != len)
goto read_failed;
rel->rd_indoption = indoption;
/* set up zeroed fmgr-info vectors */
rel->rd_aminfo = (RelationAmInfo *)
MemoryContextAllocZero(indexcxt, sizeof(RelationAmInfo));
nsupport = relform->relnatts * am->amsupport;
rel->rd_supportinfo = (FmgrInfo *)
MemoryContextAllocZero(indexcxt, nsupport * sizeof(FmgrInfo));
}
else
{
/* Count nailed rels to ensure we have 'em all */
if (rel->rd_isnailed)
nailed_rels++;
Assert(rel->rd_index == NULL);
Assert(rel->rd_indextuple == NULL); Assert(rel->rd_am == NULL);
Assert(rel->rd_indexcxt == NULL);
Assert(rel->rd_aminfo == NULL);
Assert(rel->rd_opfamily == NULL);
Assert(rel->rd_opcintype == NULL);
Assert(rel->rd_operator == NULL);
Assert(rel->rd_support == NULL);
Assert(rel->rd_supportinfo == NULL);
Assert(rel->rd_indoption == NULL);
}
/*
* Rules and triggers are not saved (mainly because the internal
* format is complex and subject to change). They must be rebuilt if
* needed by RelationCacheInitializePhase2. This is not expected to
* be a big performance hit since few system catalogs have such. Ditto
* for index expressions and predicates.
*/
rel->rd_rules = NULL;
rel->rd_rulescxt = NULL;
rel->trigdesc = NULL;
rel->rd_indexprs = NIL;
rel->rd_indpred = NIL;
/*
* Reset transient-state fields in the relcache entry
*/
rel->rd_smgr = NULL;
rel->rd_targblock = InvalidBlockNumber;
if (rel->rd_isnailed)
rel->rd_refcnt = 1;
else
rel->rd_refcnt = 0;
rel->rd_indexvalid = 0;
rel->rd_indexlist = NIL;
rel->rd_oidindex = InvalidOid;
rel->rd_createSubid = InvalidSubTransactionId;
rel->rd_newRelfilenodeSubid = InvalidSubTransactionId;
rel->rd_amcache = NULL;
MemSet(&rel->pgstat_info, 0, sizeof(rel->pgstat_info));
/*
* Recompute lock and physical addressing info. This is needed in
* case the pg_internal.init file was copied from some other database
* by CREATE DATABASE.
*/
RelationInitLockInfo(rel);
RelationInitPhysicalAddr(rel);
}
/*
* We reached the end of the init file without apparent problem. Did we
* get the right number of nailed items? (This is a useful crosscheck in
* case the set of critical rels or indexes changes.)
*/
if (nailed_rels != NUM_CRITICAL_RELS ||
nailed_indexes != NUM_CRITICAL_INDEXES)
goto read_failed;
/*
* OK, all appears well.
*
* Now insert all the new relcache entries into the cache.
*/
for (relno = 0; relno < num_rels; relno++)
{
RelationCacheInsert(rels[relno]);
/* also make a list of their OIDs, for RelationIdIsInInitFile */
initFileRelationIds = lcons_oid(RelationGetRelid(rels[relno]),
initFileRelationIds); }
pfree(rels);
FreeFile(fp);
criticalRelcachesBuilt = true;
return true;
/*
* init file is broken, so do it the hard way. We don't bother trying to
* free the clutter we just allocated; it's not in the relcache so it
* won't hurt.
*/
read_failed:
pfree(rels);
FreeFile(fp);
return false;
}
/*
* Write out a new initialization file with the current contents
* of the relcache.
*/
static void
write_relcache_init_file(void)
{
FILE *fp;
char tempfilename[MAXPGPATH];
char finalfilename[MAXPGPATH];
int magic;
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
MemoryContext oldcxt;
int i;
/*
* We must write a temporary file and rename it into place. Otherwise,
* another backend starting at about the same time might crash trying to
* read the partially-complete file.
*/
snprintf(tempfilename, sizeof(tempfilename), "%s/%s.%d",
DatabasePath, RELCACHE_INIT_FILENAME, MyProcPid);
snprintf(finalfilename, sizeof(finalfilename), "%s/%s",
DatabasePath, RELCACHE_INIT_FILENAME);
unlink(tempfilename); /* in case it exists w/wrong permissions */
fp = AllocateFile(tempfilename, PG_BINARY_W);
if (fp == NULL)
{
/*
* We used to consider this a fatal error, but we might as well
* continue with backend startup ...
*/
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not create relation-cache initialization file \"%s\": %m",
tempfilename),
errdetail("Continuing anyway, but there's something wrong.")));
return;
}
/*
* Write a magic number to serve as a file version identifier. We can
* change the magic number whenever the relcache layout changes.
*/
magic = RELCACHE_INIT_FILEMAGIC;
if (fwrite(&magic, 1, sizeof(magic), fp) != sizeof(magic))
elog(FATAL, "could not write init file");
/*
* Write all the reldescs (in no particular order).
*/
hash_seq_init(&status, RelationIdCache);
initFileRelationIds = NIL;
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
Relation rel = idhentry->reldesc;
Form_pg_class relform = rel->rd_rel;
/* first write the relcache entry proper */
write_item(rel, sizeof(RelationData), fp);
/* next write the relation tuple form */
write_item(relform, CLASS_TUPLE_SIZE, fp);
/* next, do all the attribute tuple form data entries */
for (i = 0; i < relform->relnatts; i++)
{
write_item(rel->rd_att->attrs[i], ATTRIBUTE_TUPLE_SIZE, fp);
}
/* next, do the access method specific field */
write_item(rel->rd_options,
(rel->rd_options ? VARSIZE(rel->rd_options) : 0),
fp);
/* If it's an index, there's more to do */
if (rel->rd_rel->relkind == RELKIND_INDEX)
{
Form_pg_am am = rel->rd_am;
/* write the pg_index tuple */
/* we assume this was created by heap_copytuple! */
write_item(rel->rd_indextuple,
HEAPTUPLESIZE + rel->rd_indextuple->t_len,
fp);
/* next, write the access method tuple form */
write_item(am, sizeof(FormData_pg_am), fp);
/* next, write the vector of opfamily OIDs */
write_item(rel->rd_opfamily,
relform->relnatts * sizeof(Oid),
fp);
/* next, write the vector of opcintype OIDs */
write_item(rel->rd_opcintype,
relform->relnatts * sizeof(Oid),
fp);
/* next, write the vector of operator OIDs */
write_item(rel->rd_operator,
relform->relnatts * (am->amstrategies * sizeof(Oid)),
fp);
/* next, write the vector of support procedures */
write_item(rel->rd_support,
relform->relnatts * (am->amsupport * sizeof(RegProcedure)),
fp);
/* finally, write the vector of indoption values */
write_item(rel->rd_indoption,
relform->relnatts * sizeof(int16),
fp);
}
/* also make a list of their OIDs, for RelationIdIsInInitFile */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
initFileRelationIds = lcons_oid(RelationGetRelid(rel),
initFileRelationIds);
MemoryContextSwitchTo(oldcxt);
}
if (FreeFile(fp))
elog(FATAL, "could not write init file");
/*
* Now we have to check whether the data we've so painstakingly
* accumulated is already obsolete due to someone else's just-committed
* catalog changes. If so, we just delete the temp file and leave it to
* the next backend to try again. (Our own relcache entries will be
* updated by SI message processing, but we can't be sure whether what we
* wrote out was up-to-date.)
*
* This mustn't run concurrently with RelationCacheInitFileInvalidate, so
* grab a serialization lock for the duration.
*/
LWLockAcquire(RelCacheInitLock, LW_EXCLUSIVE);
/* Make sure we have seen all incoming SI messages */
AcceptInvalidationMessages();
/*
* If we have received any SI relcache invals since backend start, assume
* we may have written out-of-date data.
*/
if (relcacheInvalsReceived == 0L)
{
/*
* OK, rename the temp file to its final name, deleting any
* previously-existing init file.
*
* Note: a failure here is possible under Cygwin, if some other
* backend is holding open an unlinked-but-not-yet-gone init file. So
* treat this as a noncritical failure; just remove the useless temp
* file on failure.
*/
if (rename(tempfilename, finalfilename) < 0)
unlink(tempfilename);
}
else
{
/* Delete the already-obsolete temp file */
unlink(tempfilename);
}
LWLockRelease(RelCacheInitLock);
}
/* write a chunk of data preceded by its length */
static void
write_item(const void *data, Size len, FILE *fp)
{
if (fwrite(&len, 1, sizeof(len), fp) != sizeof(len))
elog(FATAL, "could not write init file");
if (fwrite(data, 1, len, fp) != len)
elog(FATAL, "could not write init file");
}
/*
* Detect whether a given relation (identified by OID) is one of the ones
* we store in the init file.
*
* Note that we effectively assume that all backends running in a database
* would choose to store the same set of relations in the init file;
* otherwise there are cases where we'd fail to detect the need for an init * file invalidation. This does not seem likely to be a problem in practice.
*/
bool
RelationIdIsInInitFile(Oid relationId)
{
return list_member_oid(initFileRelationIds, relationId);
}
/*
* Invalidate (remove) the init file during commit of a transaction that
* changed one or more of the relation cache entries that are kept in the
* init file.
*
* We actually need to remove the init file twice: once just before sending
* the SI messages that include relcache inval for such relations, and once
* just after sending them. The unlink before ensures that a backend that's
* currently starting cannot read the now-obsolete init file and then miss
* the SI messages that will force it to update its relcache entries. (This
* works because the backend startup sequence gets into the PGPROC array before
* trying to load the init file.) The unlink after is to synchronize with a
* backend that may currently be trying to write an init file based on data
* that we've just rendered invalid. Such a backend will see the SI messages,
* but we can't leave the init file sitting around to fool later backends.
*
* Ignore any failure to unlink the file, since it might not be there if
* no backend has been started since the last removal.
*/
void
RelationCacheInitFileInvalidate(bool beforeSend)
{
char initfilename[MAXPGPATH];
snprintf(initfilename, sizeof(initfilename), "%s/%s",
DatabasePath, RELCACHE_INIT_FILENAME);
if (beforeSend)
{
/* no interlock needed here */
unlink(initfilename);
}
else
{
/*
* We need to interlock this against write_relcache_init_file, to
* guard against possibility that someone renames a new-but-
* already-obsolete init file into place just after we unlink. With
* the interlock, it's certain that write_relcache_init_file will
* notice our SI inval message before renaming into place, or else
* that we will execute second and successfully unlink the file.
*/
LWLockAcquire(RelCacheInitLock, LW_EXCLUSIVE);
unlink(initfilename);
LWLockRelease(RelCacheInitLock);
}
}
/*
* Remove the init file for a given database during postmaster startup.
*
* We used to keep the init file across restarts, but that is unsafe in PITR
* scenarios, and even in simple crash-recovery cases there are windows for
* the init file to become out-of-sync with the database. So now we just
* remove it during startup and expect the first backend launch to rebuild it.
* Of course, this has to happen in each database of the cluster. For
* simplicity this is driven by flatfiles.c, which has to scan pg_database
* anyway.
*/
void
RelationCacheInitFileRemove(const char *dbPath)
{ char initfilename[MAXPGPATH];
snprintf(initfilename, sizeof(initfilename), "%s/%s",
dbPath, RELCACHE_INIT_FILENAME);
unlink(initfilename);
/* ignore any error, since it might not be there at all */
}