Files
postgresql/src/include/utils/relcache.h
Noah Misch c6b92041d3 Skip WAL for new relfilenodes, under wal_level=minimal.
Until now, only selected bulk operations (e.g. COPY) did this.  If a
given relfilenode received both a WAL-skipping COPY and a WAL-logged
operation (e.g. INSERT), recovery could lose tuples from the COPY.  See
src/backend/access/transam/README section "Skipping WAL for New
RelFileNode" for the new coding rules.  Maintainers of table access
methods should examine that section.

To maintain data durability, just before commit, we choose between an
fsync of the relfilenode and copying its contents to WAL.  A new GUC,
wal_skip_threshold, guides that choice.  If this change slows a workload
that creates small, permanent relfilenodes under wal_level=minimal, try
adjusting wal_skip_threshold.  Users setting a timeout on COMMIT may
need to adjust that timeout, and log_min_duration_statement analysis
will reflect time consumption moving to COMMIT from commands like COPY.

Internally, this requires a reliable determination of whether
RollbackAndReleaseCurrentSubTransaction() would unlink a relation's
current relfilenode.  Introduce rd_firstRelfilenodeSubid.  Amend the
specification of rd_createSubid such that the field is zero when a new
rel has an old rd_node.  Make relcache.c retain entries for certain
dropped relations until end of transaction.

Bump XLOG_PAGE_MAGIC, since this introduces XLOG_GIST_ASSIGN_LSN.
Future servers accept older WAL, so this bump is discretionary.

Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert
Haas.  Heikki Linnakangas and Michael Paquier implemented earlier
designs that materially clarified the problem.  Reviewed, in earlier
designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane,
Fujii Masao, and Simon Riggs.  Reported by Martijn van Oosterhout.

Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
2020-04-04 12:25:34 -07:00

152 lines
4.6 KiB
C

/*-------------------------------------------------------------------------
*
* relcache.h
* Relation descriptor cache definitions.
*
*
* Portions Copyright (c) 1996-2020, 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 "postgres.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);
extern Datum *RelationGetIndexRawAttOptions(Relation relation);
extern bytea **RelationGetIndexAttOptions(Relation relation, bool copy);
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);
/*
* Routines to manage assignment of new relfilenode to a relation
*/
extern void RelationSetNewRelfilenode(Relation relation, char persistence);
extern void RelationAssumeNewRelfilenode(Relation relation);
/*
* 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);
#ifdef USE_ASSERT_CHECKING
extern void AssertPendingSyncs_RelationCache(void);
#else
#define AssertPendingSyncs_RelationCache() do {} while (0)
#endif
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 */