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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
commit46651ce6fe013220ed397add242004d764fc0153 (patch)
tree6e5299f990f88e60174a1d3ae6e48eedd2688b2b /src/include/utils/catcache.h
parentInitial commit. (diff)
downloadpostgresql-14-46651ce6fe013220ed397add242004d764fc0153.tar.xz
postgresql-14-46651ce6fe013220ed397add242004d764fc0153.zip
Adding upstream version 14.5.upstream/14.5upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+/*-------------------------------------------------------------------------
+ *
+ * catcache.h
+ * Low-level catalog cache definitions.
+ *
+ * NOTE: every catalog cache must have a corresponding unique index on
+ * the system table that it caches --- ie, the index must match the keys
+ * used to do lookups in this cache. All cache fetches are done with
+ * indexscans (under normal conditions). The index should be unique to
+ * guarantee that there can only be one matching row for a key combination.
+ *
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/utils/catcache.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef CATCACHE_H
+#define CATCACHE_H
+
+#include "access/htup.h"
+#include "access/skey.h"
+#include "lib/ilist.h"
+#include "utils/relcache.h"
+
+/*
+ * struct catctup: individual tuple in the cache.
+ * struct catclist: list of tuples matching a partial key.
+ * struct catcache: information for managing a cache.
+ * struct catcacheheader: information for managing all the caches.
+ */
+
+#define CATCACHE_MAXKEYS 4
+
+
+/* function computing a datum's hash */
+typedef uint32 (*CCHashFN) (Datum datum);
+
+/* function computing equality of two datums */
+typedef bool (*CCFastEqualFN) (Datum a, Datum b);
+
+typedef struct catcache
+{
+ int id; /* cache identifier --- see syscache.h */
+ int cc_nbuckets; /* # of hash buckets in this cache */
+ TupleDesc cc_tupdesc; /* tuple descriptor (copied from reldesc) */
+ dlist_head *cc_bucket; /* hash buckets */
+ CCHashFN cc_hashfunc[CATCACHE_MAXKEYS]; /* hash function for each key */
+ CCFastEqualFN cc_fastequal[CATCACHE_MAXKEYS]; /* fast equal function for
+ * each key */
+ int cc_keyno[CATCACHE_MAXKEYS]; /* AttrNumber of each key */
+ dlist_head cc_lists; /* list of CatCList structs */
+ int cc_ntup; /* # of tuples currently in this cache */
+ int cc_nkeys; /* # of keys (1..CATCACHE_MAXKEYS) */
+ const char *cc_relname; /* name of relation the tuples come from */
+ Oid cc_reloid; /* OID of relation the tuples come from */
+ Oid cc_indexoid; /* OID of index matching cache keys */
+ bool cc_relisshared; /* is relation shared across databases? */
+ slist_node cc_next; /* list link */
+ ScanKeyData cc_skey[CATCACHE_MAXKEYS]; /* precomputed key info for heap
+ * scans */
+
+ /*
+ * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS
+ * doesn't break ABI for other modules
+ */
+#ifdef CATCACHE_STATS
+ long cc_searches; /* total # searches against this cache */
+ long cc_hits; /* # of matches against existing entry */
+ long cc_neg_hits; /* # of matches against negative entry */
+ long cc_newloads; /* # of successful loads of new entry */
+
+ /*
+ * cc_searches - (cc_hits + cc_neg_hits + cc_newloads) is number of failed
+ * searches, each of which will result in loading a negative entry
+ */
+ long cc_invals; /* # of entries invalidated from cache */
+ long cc_lsearches; /* total # list-searches */
+ long cc_lhits; /* # of matches against existing lists */
+#endif
+} CatCache;
+
+
+typedef struct catctup
+{
+ int ct_magic; /* for identifying CatCTup entries */
+#define CT_MAGIC 0x57261502
+
+ uint32 hash_value; /* hash value for this tuple's keys */
+
+ /*
+ * Lookup keys for the entry. By-reference datums point into the tuple for
+ * positive cache entries, and are separately allocated for negative ones.
+ */
+ Datum keys[CATCACHE_MAXKEYS];
+
+ /*
+ * Each tuple in a cache is a member of a dlist that stores the elements
+ * of its hash bucket. We keep each dlist in LRU order to speed repeated
+ * lookups.
+ */
+ dlist_node cache_elem; /* list member of per-bucket list */
+
+ /*
+ * A tuple marked "dead" must not be returned by subsequent searches.
+ * However, it won't be physically deleted from the cache until its
+ * refcount goes to zero. (If it's a member of a CatCList, the list's
+ * refcount must go to zero, too; also, remember to mark the list dead at
+ * the same time the tuple is marked.)
+ *
+ * A negative cache entry is an assertion that there is no tuple matching
+ * a particular key. This is just as useful as a normal entry so far as
+ * avoiding catalog searches is concerned. Management of positive and
+ * negative entries is identical.
+ */
+ int refcount; /* number of active references */
+ bool dead; /* dead but not yet removed? */
+ bool negative; /* negative cache entry? */
+ HeapTupleData tuple; /* tuple management header */
+
+ /*
+ * The tuple may also be a member of at most one CatCList. (If a single
+ * catcache is list-searched with varying numbers of keys, we may have to
+ * make multiple entries for the same tuple because of this restriction.
+ * Currently, that's not expected to be common, so we accept the potential
+ * inefficiency.)
+ */
+ struct catclist *c_list; /* containing CatCList, or NULL if none */
+
+ CatCache *my_cache; /* link to owning catcache */
+ /* properly aligned tuple data follows, unless a negative entry */
+} CatCTup;
+
+
+/*
+ * A CatCList describes the result of a partial search, ie, a search using
+ * only the first K key columns of an N-key cache. We store the keys used
+ * into the keys attribute to represent the stored key set. The CatCList
+ * object contains links to cache entries for all the table rows satisfying
+ * the partial key. (Note: none of these will be negative cache entries.)
+ *
+ * A CatCList is only a member of a per-cache list; we do not currently
+ * divide them into hash buckets.
+ *
+ * A list marked "dead" must not be returned by subsequent searches.
+ * However, it won't be physically deleted from the cache until its
+ * refcount goes to zero. (A list should be marked dead if any of its
+ * member entries are dead.)
+ *
+ * If "ordered" is true then the member tuples appear in the order of the
+ * cache's underlying index. This will be true in normal operation, but
+ * might not be true during bootstrap or recovery operations. (namespace.c
+ * is able to save some cycles when it is true.)
+ */
+typedef struct catclist
+{
+ int cl_magic; /* for identifying CatCList entries */
+#define CL_MAGIC 0x52765103
+
+ uint32 hash_value; /* hash value for lookup keys */
+
+ dlist_node cache_elem; /* list member of per-catcache list */
+
+ /*
+ * Lookup keys for the entry, with the first nkeys elements being valid.
+ * All by-reference are separately allocated.
+ */
+ Datum keys[CATCACHE_MAXKEYS];
+
+ int refcount; /* number of active references */
+ bool dead; /* dead but not yet removed? */
+ bool ordered; /* members listed in index order? */
+ short nkeys; /* number of lookup keys specified */
+ int n_members; /* number of member tuples */
+ CatCache *my_cache; /* link to owning catcache */
+ CatCTup *members[FLEXIBLE_ARRAY_MEMBER]; /* members */
+} CatCList;
+
+
+typedef struct catcacheheader
+{
+ slist_head ch_caches; /* head of list of CatCache structs */
+ int ch_ntup; /* # of tuples in all caches */
+} CatCacheHeader;
+
+
+/* this extern duplicates utils/memutils.h... */
+extern PGDLLIMPORT MemoryContext CacheMemoryContext;
+
+extern void CreateCacheMemoryContext(void);
+
+extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid,
+ int nkeys, const int *key,
+ int nbuckets);
+extern void InitCatCachePhase2(CatCache *cache, bool touch_index);
+
+extern HeapTuple SearchCatCache(CatCache *cache,
+ Datum v1, Datum v2, Datum v3, Datum v4);
+extern HeapTuple SearchCatCache1(CatCache *cache,
+ Datum v1);
+extern HeapTuple SearchCatCache2(CatCache *cache,
+ Datum v1, Datum v2);
+extern HeapTuple SearchCatCache3(CatCache *cache,
+ Datum v1, Datum v2, Datum v3);
+extern HeapTuple SearchCatCache4(CatCache *cache,
+ Datum v1, Datum v2, Datum v3, Datum v4);
+extern void ReleaseCatCache(HeapTuple tuple);
+
+extern uint32 GetCatCacheHashValue(CatCache *cache,
+ Datum v1, Datum v2,
+ Datum v3, Datum v4);
+
+extern CatCList *SearchCatCacheList(CatCache *cache, int nkeys,
+ Datum v1, Datum v2,
+ Datum v3);
+extern void ReleaseCatCacheList(CatCList *list);
+
+extern void ResetCatalogCaches(void);
+extern void CatalogCacheFlushCatalog(Oid catId);
+extern void CatCacheInvalidate(CatCache *cache, uint32 hashValue);
+extern void PrepareToInvalidateCacheTuple(Relation relation,
+ HeapTuple tuple,
+ HeapTuple newtuple,
+ void (*function) (int, uint32, Oid));
+
+extern void PrintCatCacheLeakWarning(HeapTuple tuple);
+extern void PrintCatCacheListLeakWarning(CatCList *list);
+
+#endif /* CATCACHE_H */