trAvis - MANAGER

Edit File: catcache.h

/*------------------------------------------------------------------------- * * 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) 1996-2012, 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/dllist.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 typedef struct catcache { int id; /* cache identifier --- see syscache.h */ struct catcache *cc_next; /* link to next catcache */ 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? */ TupleDesc cc_tupdesc; /* tuple descriptor (copied from reldesc) */ int cc_ntup; /* # of tuples currently in this cache */ int cc_nbuckets; /* # of hash buckets in this cache */ int cc_nkeys; /* # of keys (1..CATCACHE_MAXKEYS) */ int cc_key[CATCACHE_MAXKEYS]; /* AttrNumber of each key */ PGFunction cc_hashfunc[CATCACHE_MAXKEYS]; /* hash function for each key */ ScanKeyData cc_skey[CATCACHE_MAXKEYS]; /* precomputed key info for * heap scans */ bool cc_isname[CATCACHE_MAXKEYS]; /* flag "name" key columns */ Dllist cc_lists; /* list of CatCList structs */ #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 Dllist cc_bucket[1]; /* hash buckets --- VARIABLE LENGTH ARRAY */ } CatCache; /* VARIABLE LENGTH STRUCT */ typedef struct catctup { int ct_magic; /* for identifying CatCTup entries */ #define CT_MAGIC 0x57261502 CatCache *my_cache; /* link to owning catcache */ /* * Each tuple in a cache is a member of a Dllist that stores the elements * of its hash bucket. We keep each Dllist in LRU order to speed repeated * lookups. */ Dlelem cache_elem; /* list member of per-bucket list */ /* * 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 */ /* * 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? */ uint32 hash_value; /* hash value for this tuple's keys */ HeapTupleData tuple; /* tuple management header */ } CatCTup; typedef struct catclist { int cl_magic; /* for identifying CatCList entries */ #define CL_MAGIC 0x52765103 CatCache *my_cache; /* link to owning catcache */ /* * 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 form the keys used * into a tuple (with other attributes NULL) 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.) */ Dlelem cache_elem; /* list member of per-catcache list */ 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 */ uint32 hash_value; /* hash value for lookup keys */ HeapTupleData tuple; /* header for tuple holding keys */ int n_members; /* number of member tuples */ CatCTup *members[1]; /* members --- VARIABLE LENGTH ARRAY */ } CatCList; /* VARIABLE LENGTH STRUCT */ typedef struct catcacheheader { CatCache *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 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, Datum v4); extern void ReleaseCatCacheList(CatCList *list); extern void ResetCatalogCaches(void); extern void CatalogCacheFlushCatalog(Oid catId); extern void CatalogCacheIdInvalidate(int cacheId, 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 */