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7b504eb282
Add support for explicitly declared statistic objects (CREATE STATISTICS), allowing collection of statistics on more complex combinations that individual table columns. Companion commands DROP STATISTICS and ALTER STATISTICS ... OWNER TO / SET SCHEMA / RENAME are added too. All this DDL has been designed so that more statistic types can be added later on, such as multivariate most-common-values and multivariate histograms between columns of a single table, leaving room for permitting columns on multiple tables, too, as well as expressions. This commit only adds support for collection of n-distinct coefficient on user-specified sets of columns in a single table. This is useful to estimate number of distinct groups in GROUP BY and DISTINCT clauses; estimation errors there can cause over-allocation of memory in hashed aggregates, for instance, so it's a worthwhile problem to solve. A new special pseudo-type pg_ndistinct is used. (num-distinct estimation was deemed sufficiently useful by itself that this is worthwhile even if no further statistic types are added immediately; so much so that another version of essentially the same functionality was submitted by Kyotaro Horiguchi: https://postgr.es/m/20150828.173334.114731693.horiguchi.kyotaro@lab.ntt.co.jp though this commit does not use that code.) Author: Tomas Vondra. Some code rework by Álvaro. Reviewed-by: Dean Rasheed, David Rowley, Kyotaro Horiguchi, Jeff Janes, Ideriha Takeshi Discussion: https://postgr.es/m/543AFA15.4080608@fuzzy.cz https://postgr.es/m/20170320190220.ixlaueanxegqd5gr@alvherre.pgsql
138 lines
4.1 KiB
C
138 lines
4.1 KiB
C
/*-------------------------------------------------------------------------
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*
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* relcache.h
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* Relation descriptor cache definitions.
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*
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*
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* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/utils/relcache.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef RELCACHE_H
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#define RELCACHE_H
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#include "access/tupdesc.h"
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#include "nodes/bitmapset.h"
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typedef struct RelationData *Relation;
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/* ----------------
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* RelationPtr is used in the executor to support index scans
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* where we have to keep track of several index relations in an
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* array. -cim 9/10/89
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* ----------------
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*/
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typedef Relation *RelationPtr;
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/*
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* Routines to open (lookup) and close a relcache entry
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*/
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extern Relation RelationIdGetRelation(Oid relationId);
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extern void RelationClose(Relation relation);
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/*
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* Routines to compute/retrieve additional cached information
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*/
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extern List *RelationGetFKeyList(Relation relation);
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extern List *RelationGetIndexList(Relation relation);
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extern List *RelationGetStatExtList(Relation relation);
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extern Oid RelationGetOidIndex(Relation relation);
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extern Oid RelationGetPrimaryKeyIndex(Relation relation);
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extern Oid RelationGetReplicaIndex(Relation relation);
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extern List *RelationGetIndexExpressions(Relation relation);
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extern List *RelationGetIndexPredicate(Relation relation);
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typedef enum IndexAttrBitmapKind
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{
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INDEX_ATTR_BITMAP_ALL,
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INDEX_ATTR_BITMAP_KEY,
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INDEX_ATTR_BITMAP_PRIMARY_KEY,
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INDEX_ATTR_BITMAP_IDENTITY_KEY
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} IndexAttrBitmapKind;
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extern Bitmapset *RelationGetIndexAttrBitmap(Relation relation,
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IndexAttrBitmapKind keyAttrs);
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extern void RelationGetExclusionInfo(Relation indexRelation,
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Oid **operators,
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Oid **procs,
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uint16 **strategies);
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extern void RelationSetIndexList(Relation relation,
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List *indexIds, Oid oidIndex);
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extern void RelationInitIndexAccessInfo(Relation relation);
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/* caller must include pg_publication.h */
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struct PublicationActions;
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extern struct PublicationActions *GetRelationPublicationActions(Relation relation);
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/*
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* Routines to support ereport() reports of relation-related errors
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*/
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extern int errtable(Relation rel);
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extern int errtablecol(Relation rel, int attnum);
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extern int errtablecolname(Relation rel, const char *colname);
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extern int errtableconstraint(Relation rel, const char *conname);
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/*
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* Routines for backend startup
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*/
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extern void RelationCacheInitialize(void);
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extern void RelationCacheInitializePhase2(void);
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extern void RelationCacheInitializePhase3(void);
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/*
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* Routine to create a relcache entry for an about-to-be-created relation
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*/
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extern Relation RelationBuildLocalRelation(const char *relname,
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Oid relnamespace,
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TupleDesc tupDesc,
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Oid relid,
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Oid relfilenode,
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Oid reltablespace,
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bool shared_relation,
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bool mapped_relation,
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char relpersistence,
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char relkind);
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/*
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* Routine to manage assignment of new relfilenode to a relation
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*/
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extern void RelationSetNewRelfilenode(Relation relation, char persistence,
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TransactionId freezeXid, MultiXactId minmulti);
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/*
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* Routines for flushing/rebuilding relcache entries in various scenarios
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*/
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extern void RelationForgetRelation(Oid rid);
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extern void RelationCacheInvalidateEntry(Oid relationId);
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extern void RelationCacheInvalidate(void);
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extern void RelationCloseSmgrByOid(Oid relationId);
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extern void AtEOXact_RelationCache(bool isCommit);
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extern void AtEOSubXact_RelationCache(bool isCommit, SubTransactionId mySubid,
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SubTransactionId parentSubid);
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/*
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* Routines to help manage rebuilding of relcache init files
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*/
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extern bool RelationIdIsInInitFile(Oid relationId);
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extern void RelationCacheInitFilePreInvalidate(void);
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extern void RelationCacheInitFilePostInvalidate(void);
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extern void RelationCacheInitFileRemove(void);
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/* should be used only by relcache.c and catcache.c */
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extern bool criticalRelcachesBuilt;
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/* should be used only by relcache.c and postinit.c */
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extern bool criticalSharedRelcachesBuilt;
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#endif /* RELCACHE_H */
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