diff options
Diffstat (limited to 'src/backend/utils/cache/catcache.c')
| -rw-r--r-- | src/backend/utils/cache/catcache.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index ecf0f87c749..6cb7b65fe3f 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.91 2002/03/06 06:10:21 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.92 2002/03/06 20:49:45 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -39,7 +39,7 @@ /* * Constants related to size of the catcache. * - * NCCBUCKETS should be prime and must be less than 64K (because + * NCCBUCKETS must be a power of two and must be less than 64K (because * SharedInvalCatcacheMsg crams hash indexes into a uint16 field). In * practice it should be a lot less, anyway, to avoid chewing up too much * space on hash bucket headers. @@ -47,9 +47,16 @@ * MAXCCTUPLES could be as small as a few hundred, if per-backend memory * consumption is at a premium. */ -#define NCCBUCKETS 257 /* Hash buckets per CatCache */ +#define NCCBUCKETS 256 /* Hash buckets per CatCache */ #define MAXCCTUPLES 5000 /* Maximum # of tuples in all caches */ +/* + * Given a hash value and the size of the hash table, find the bucket + * in which the hash value belongs. Since the hash table must contain + * a power-of-2 number of elements, this is a simple bitmask. + */ +#define HASH_INDEX(h, sz) ((Index) ((h) & ((sz) - 1))) + /* * variables, macros and other stuff @@ -380,7 +387,7 @@ CatalogCacheIdInvalidate(int cacheId, /* * inspect the proper hash bucket for matches */ - hashIndex = (Index) (hashValue % (uint32) ccp->cc_size); + hashIndex = HASH_INDEX(hashValue, ccp->cc_nbuckets); for (elt = DLGetHead(&ccp->cc_bucket[hashIndex]); elt; elt = nextelt) { @@ -490,7 +497,7 @@ ResetCatalogCache(CatCache *cache) int i; /* Remove each tuple in this cache, or at least mark it dead */ - for (i = 0; i < cache->cc_size; i++) + for (i = 0; i < cache->cc_nbuckets; i++) { Dlelem *elt, *nextelt; @@ -578,7 +585,7 @@ CatalogCacheFlushRelation(Oid relId) continue; /* nope, leave it alone */ /* Yes, scan the tuples and remove those related to relId */ - for (i = 0; i < cache->cc_size; i++) + for (i = 0; i < cache->cc_nbuckets; i++) { Dlelem *elt, *nextelt; @@ -640,7 +647,7 @@ CatalogCacheFlushRelation(Oid relId) #define InitCatCache_DEBUG1 \ do { \ elog(DEBUG1, "InitCatCache: rel=%s id=%d nkeys=%d size=%d\n", \ - cp->cc_relname, cp->id, cp->cc_nkeys, cp->cc_size); \ + cp->cc_relname, cp->id, cp->cc_nkeys, cp->cc_nbuckets); \ } while(0) #else @@ -705,7 +712,7 @@ InitCatCache(int id, cp->cc_tupdesc = (TupleDesc) NULL; cp->cc_reloidattr = reloidattr; cp->cc_ntup = 0; - cp->cc_size = NCCBUCKETS; + cp->cc_nbuckets = NCCBUCKETS; cp->cc_nkeys = nkeys; for (i = 0; i < nkeys; ++i) cp->cc_key[i] = key[i]; @@ -985,7 +992,7 @@ SearchCatCache(CatCache *cache, * find the hash bucket in which to look for the tuple */ hashValue = CatalogCacheComputeHashValue(cache, cur_skey); - hashIndex = (Index) (hashValue % (uint32) cache->cc_size); + hashIndex = HASH_INDEX(hashValue, cache->cc_nbuckets); /* * scan the hash bucket until we find a match or exhaust our tuples |