Files
postgresql/src/include/utils/relcache.h
Tom Lane 2ada6779c5 Fix race condition in relcache init file invalidation.
The previous code tried to synchronize by unlinking the init file twice,
but that doesn't actually work: it leaves a window wherein a third process
could read the already-stale init file but miss the SI messages that would
tell it the data is stale.  The result would be bizarre failures in catalog
accesses, typically "could not read block 0 in file ..." later during
startup.

Instead, hold RelCacheInitLock across both the unlink and the sending of
the SI messages.  This is more straightforward, and might even be a bit
faster since only one unlink call is needed.

This has been wrong since it was put in (in 2002!), so back-patch to all
supported releases.
2011-08-16 13:11:54 -04:00

112 lines
3.2 KiB
C

/*-------------------------------------------------------------------------
*
* relcache.h
* Relation descriptor cache definitions.
*
*
* Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/utils/relcache.h
*
*-------------------------------------------------------------------------
*/
#ifndef RELCACHE_H
#define RELCACHE_H
#include "access/tupdesc.h"
#include "nodes/bitmapset.h"
#include "nodes/pg_list.h"
typedef struct RelationData *Relation;
/* ----------------
* RelationPtr is used in the executor to support index scans
* where we have to keep track of several index relations in an
* array. -cim 9/10/89
* ----------------
*/
typedef Relation *RelationPtr;
/*
* Routines to open (lookup) and close a relcache entry
*/
extern Relation RelationIdGetRelation(Oid relationId);
extern void RelationClose(Relation relation);
/*
* Routines to compute/retrieve additional cached information
*/
extern List *RelationGetIndexList(Relation relation);
extern Oid RelationGetOidIndex(Relation relation);
extern List *RelationGetIndexExpressions(Relation relation);
extern List *RelationGetIndexPredicate(Relation relation);
extern Bitmapset *RelationGetIndexAttrBitmap(Relation relation);
extern void RelationGetExclusionInfo(Relation indexRelation,
Oid **operators,
Oid **procs,
uint16 **strategies);
extern void RelationSetIndexList(Relation relation,
List *indexIds, Oid oidIndex);
extern void RelationInitIndexAccessInfo(Relation relation);
/*
* Routines for backend startup
*/
extern void RelationCacheInitialize(void);
extern void RelationCacheInitializePhase2(void);
extern void RelationCacheInitializePhase3(void);
/*
* Routine to create a relcache entry for an about-to-be-created relation
*/
extern Relation RelationBuildLocalRelation(const char *relname,
Oid relnamespace,
TupleDesc tupDesc,
Oid relid,
Oid relfilenode,
Oid reltablespace,
bool shared_relation,
bool mapped_relation,
char relpersistence);
/*
* Routine to manage assignment of new relfilenode to a relation
*/
extern void RelationSetNewRelfilenode(Relation relation,
TransactionId freezeXid);
/*
* Routines for flushing/rebuilding relcache entries in various scenarios
*/
extern void RelationForgetRelation(Oid rid);
extern void RelationCacheInvalidateEntry(Oid relationId);
extern void RelationCacheInvalidate(void);
extern void RelationCloseSmgrByOid(Oid relationId);
extern void AtEOXact_RelationCache(bool isCommit);
extern void AtEOSubXact_RelationCache(bool isCommit, SubTransactionId mySubid,
SubTransactionId parentSubid);
/*
* Routines to help manage rebuilding of relcache init files
*/
extern bool RelationIdIsInInitFile(Oid relationId);
extern void RelationCacheInitFilePreInvalidate(void);
extern void RelationCacheInitFilePostInvalidate(void);
extern void RelationCacheInitFileRemove(void);
/* should be used only by relcache.c and catcache.c */
extern bool criticalRelcachesBuilt;
/* should be used only by relcache.c and postinit.c */
extern bool criticalSharedRelcachesBuilt;
#endif /* RELCACHE_H */