Files
postgresql/src/include/utils/relcache.h
Tom Lane c35b714caf Fix misbehavior with expression indexes on ON COMMIT DELETE ROWS tables.
We implement ON COMMIT DELETE ROWS by truncating tables marked that
way, which requires also truncating/rebuilding their indexes.  But
RelationTruncateIndexes asks the relcache for up-to-date copies of any
index expressions, which may cause execution of eval_const_expressions
on them, which can result in actual execution of subexpressions.
This is a bad thing to have happening during ON COMMIT.  Manuel Rigger
reported that use of a SQL function resulted in crashes due to
expectations that ActiveSnapshot would be set, which it isn't.
The most obvious fix perhaps would be to push a snapshot during
PreCommit_on_commit_actions, but I think that would just open the door
to more problems: CommitTransaction explicitly expects that no
user-defined code can be running at this point.

Fortunately, since we know that no tuples exist to be indexed, there
seems no need to use the real index expressions or predicates during
RelationTruncateIndexes.  We can set up dummy index expressions
instead (we do need something that will expose the right data type,
as there are places that build index tupdescs based on this), and
just ignore predicates and exclusion constraints.

In a green field it'd likely be better to reimplement ON COMMIT DELETE
ROWS using the same "init fork" infrastructure used for unlogged
relations.  That seems impractical without catalog changes though,
and even without that it'd be too big a change to back-patch.
So for now do it like this.

Per private report from Manuel Rigger.  This has been broken forever,
so back-patch to all supported branches.
2019-12-01 13:09:26 -05:00

143 lines
4.2 KiB
C

/*-------------------------------------------------------------------------
*
* relcache.h
* Relation descriptor cache definitions.
*
*
* Portions Copyright (c) 1996-2019, 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"
/*
* Name of relcache init file(s), used to speed up backend startup
*/
#define RELCACHE_INIT_FILENAME "pg_internal.init"
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 *RelationGetFKeyList(Relation relation);
extern List *RelationGetIndexList(Relation relation);
extern List *RelationGetStatExtList(Relation relation);
extern Oid RelationGetPrimaryKeyIndex(Relation relation);
extern Oid RelationGetReplicaIndex(Relation relation);
extern List *RelationGetIndexExpressions(Relation relation);
extern List *RelationGetDummyIndexExpressions(Relation relation);
extern List *RelationGetIndexPredicate(Relation relation);
typedef enum IndexAttrBitmapKind
{
INDEX_ATTR_BITMAP_ALL,
INDEX_ATTR_BITMAP_KEY,
INDEX_ATTR_BITMAP_PRIMARY_KEY,
INDEX_ATTR_BITMAP_IDENTITY_KEY
} IndexAttrBitmapKind;
extern Bitmapset *RelationGetIndexAttrBitmap(Relation relation,
IndexAttrBitmapKind attrKind);
extern void RelationGetExclusionInfo(Relation indexRelation,
Oid **operators,
Oid **procs,
uint16 **strategies);
extern void RelationInitIndexAccessInfo(Relation relation);
/* caller must include pg_publication.h */
struct PublicationActions;
extern struct PublicationActions *GetRelationPublicationActions(Relation relation);
extern void RelationInitTableAccessMethod(Relation relation);
/*
* Routines to support ereport() reports of relation-related errors
*/
extern int errtable(Relation rel);
extern int errtablecol(Relation rel, int attnum);
extern int errtablecolname(Relation rel, const char *colname);
extern int errtableconstraint(Relation rel, const char *conname);
/*
* 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 accessmtd,
Oid relfilenode,
Oid reltablespace,
bool shared_relation,
bool mapped_relation,
char relpersistence,
char relkind);
/*
* Routine to manage assignment of new relfilenode to a relation
*/
extern void RelationSetNewRelfilenode(Relation relation, char persistence);
/*
* 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 */