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7863404417
Improve 'pg_internal.init' relcache entry preload mechanism so that it is safe to use for all system catalogs, and arrange to preload a realistic set of system-catalog entries instead of only the three nailed-in-cache indexes that were formerly loaded this way. Fix mechanism for deleting out-of-date pg_internal.init files: this must be synchronized with transaction commit, not just done at random times within transactions. Drive it off relcache invalidation mechanism so that no special-case tests are needed. Cache additional information in relcache entries for indexes (their pg_index tuples and index-operator OIDs) to eliminate repeated lookups. Also cache index opclass info at the per-opclass level to avoid repeated lookups during relcache load. Generalize 'systable scan' utilities originally developed by Hiroshi, move them into genam.c, use in a number of places where there was formerly ugly code for choosing either heap or index scan. In particular this allows simplification of the logic that prevents infinite recursion between syscache and relcache during startup: we can easily switch to heapscans in relcache.c when and where needed to avoid recursion, so IndexScanOK becomes simpler and does not need any expensive initialization. Eliminate useless opening of a heapscan data structure while doing an indexscan (this saves an mdnblocks call and thus at least one kernel call).
114 lines
4.1 KiB
C
114 lines
4.1 KiB
C
/*-------------------------------------------------------------------------
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*
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* catcache.h
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* Low-level catalog cache definitions.
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*
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* NOTE: every catalog cache must have a corresponding unique index on
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* the system table that it caches --- ie, the index must match the keys
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* used to do lookups in this cache. All cache fetches are done with
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* indexscans (under normal conditions). The index should be unique to
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* guarantee that there can only be one matching row for a key combination.
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*
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*
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* Portions Copyright (c) 1996-2001, 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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* $Id: catcache.h,v 1.38 2002/02/19 20:11:19 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef CATCACHE_H
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#define CATCACHE_H
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#include "access/htup.h"
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#include "lib/dllist.h"
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/*
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* struct catctup: individual tuple in the cache.
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* struct catcache: information for managing a cache.
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* struct catcacheheader: information for managing all the caches.
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*/
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typedef struct catcache
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{
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int id; /* cache identifier --- see syscache.h */
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struct catcache *cc_next; /* link to next catcache */
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char *cc_relname; /* name of relation the tuples come from */
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char *cc_indname; /* name of index matching cache keys */
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int cc_reloidattr; /* AttrNumber of relation OID, or 0 */
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bool cc_relisshared; /* is relation shared? */
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TupleDesc cc_tupdesc; /* tuple descriptor (copied from reldesc) */
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int cc_ntup; /* # of tuples currently in this cache */
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int cc_size; /* # of hash buckets in this cache */
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int cc_nkeys; /* number of keys (1..4) */
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int cc_key[4]; /* AttrNumber of each key */
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PGFunction cc_hashfunc[4]; /* hash function to use for each key */
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ScanKeyData cc_skey[4]; /* precomputed key info for heap scans */
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#ifdef CATCACHE_STATS
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long cc_searches; /* total # searches against this cache */
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long cc_hits; /* # of matches against existing entry */
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long cc_newloads; /* # of successful loads of new entry */
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/* cc_searches - (cc_hits + cc_newloads) is # of failed searches */
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#endif
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Dllist cc_bucket[1]; /* hash buckets --- VARIABLE LENGTH ARRAY */
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} CatCache; /* VARIABLE LENGTH STRUCT */
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typedef struct catctup
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{
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int ct_magic; /* for Assert checks */
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#define CT_MAGIC 0x57261502
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CatCache *my_cache; /* link to owning catcache */
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/*
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* Each tuple in a cache is a member of two lists: one lists all the
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* elements in all the caches in LRU order, and the other lists just
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* the elements in one hashbucket of one cache, also in LRU order.
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*
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* A tuple marked "dead" must not be returned by subsequent searches.
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* However, it won't be physically deleted from the cache until its
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* refcount goes to zero.
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*/
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Dlelem lrulist_elem; /* list member of global LRU list */
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Dlelem cache_elem; /* list member of per-bucket list */
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int refcount; /* number of active references */
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bool dead; /* dead but not yet removed? */
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HeapTupleData tuple; /* tuple management header */
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} CatCTup;
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typedef struct catcacheheader
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{
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CatCache *ch_caches; /* head of list of CatCache structs */
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int ch_ntup; /* # of tuples in all caches */
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int ch_maxtup; /* max # of tuples allowed (LRU) */
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Dllist ch_lrulist; /* overall LRU list, most recent first */
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} CatCacheHeader;
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/* this extern duplicates utils/memutils.h... */
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extern MemoryContext CacheMemoryContext;
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extern void CreateCacheMemoryContext(void);
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extern void AtEOXact_CatCache(bool isCommit);
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extern CatCache *InitCatCache(int id, char *relname, char *indname,
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int reloidattr,
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int nkeys, int *key);
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extern void InitCatCachePhase2(CatCache *cache);
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extern HeapTuple SearchCatCache(CatCache *cache,
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Datum v1, Datum v2,
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Datum v3, Datum v4);
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extern void ReleaseCatCache(HeapTuple tuple);
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extern void ResetCatalogCaches(void);
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extern void CatalogCacheFlushRelation(Oid relId);
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extern void CatalogCacheIdInvalidate(int cacheId, Index hashIndex,
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ItemPointer pointer);
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extern void PrepareToInvalidateCacheTuple(Relation relation,
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HeapTuple tuple,
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void (*function) (int, Index, ItemPointer, Oid));
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#endif /* CATCACHE_H */
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