Marginal hack to use a specialized hash function for dynahash hashtables

whose keys are OIDs.  The only one that looks particularly performance
critical is the relcache hashtable, but as long as we've got the function
we may as well use it wherever it's applicable.

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index ce4dc45..e21adab 100644 (file)
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -13,7 +13,7 @@
  *
  *     Copyright (c) 2001-2005, PostgreSQL Global Development Group
  *
- *     $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.91 2005/04/14 20:03:25 tgl Exp $
+ *     $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.92 2005/04/14 20:32:42 tgl Exp $
  * ----------
  */
 #include "postgres.h"
@@ -2065,7 +2065,7 @@ pgstat_add_backend(PgStat_MsgHdr *msg)
                memset(&hash_ctl, 0, sizeof(hash_ctl));
                hash_ctl.keysize = sizeof(Oid);
                hash_ctl.entrysize = sizeof(PgStat_StatTabEntry);
-               hash_ctl.hash = tag_hash;
+               hash_ctl.hash = oid_hash;
                dbentry->tables = hash_create("Per-database table",
                                                                          PGSTAT_TAB_HASH_SIZE,
                                                                          &hash_ctl,
@@ -2364,7 +2364,7 @@ pgstat_read_statsfile(HTAB **dbhash, Oid onlydb,
        memset(&hash_ctl, 0, sizeof(hash_ctl));
        hash_ctl.keysize = sizeof(Oid);
        hash_ctl.entrysize = sizeof(PgStat_StatDBEntry);
-       hash_ctl.hash = tag_hash;
+       hash_ctl.hash = oid_hash;
        hash_ctl.hcxt = use_mcxt;
        *dbhash = hash_create("Databases hash", PGSTAT_DB_HASH_SIZE, &hash_ctl,
                                                  HASH_ELEM | HASH_FUNCTION | mcxt_flags);
@@ -2453,7 +2453,7 @@ pgstat_read_statsfile(HTAB **dbhash, Oid onlydb,
                                memset(&hash_ctl, 0, sizeof(hash_ctl));
                                hash_ctl.keysize = sizeof(Oid);
                                hash_ctl.entrysize = sizeof(PgStat_StatTabEntry);
-                               hash_ctl.hash = tag_hash;
+                               hash_ctl.hash = oid_hash;
                                hash_ctl.hcxt = use_mcxt;
                                dbentry->tables = hash_create("Per-database table",
                                                                                          PGSTAT_TAB_HASH_SIZE,
@@ -2888,7 +2888,7 @@ pgstat_recv_resetcounter(PgStat_MsgResetcounter *msg, int len)
        memset(&hash_ctl, 0, sizeof(hash_ctl));
        hash_ctl.keysize = sizeof(Oid);
        hash_ctl.entrysize = sizeof(PgStat_StatTabEntry);
-       hash_ctl.hash = tag_hash;
+       hash_ctl.hash = oid_hash;
        dbentry->tables = hash_create("Per-database table",
                                                                  PGSTAT_TAB_HASH_SIZE,
                                                                  &hash_ctl,

diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ab773de..7c24e64 100644 (file)
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.220 2005/04/14 20:03:26 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.221 2005/04/14 20:32:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1032,7 +1032,7 @@ LookupOpclassInfo(Oid operatorClassOid,
                MemSet(&ctl, 0, sizeof(ctl));
                ctl.keysize = sizeof(Oid);
                ctl.entrysize = sizeof(OpClassCacheEnt);
-               ctl.hash = tag_hash;
+               ctl.hash = oid_hash;
                OpClassCache = hash_create("Operator class cache", 64,
                                                                   &ctl, HASH_ELEM | HASH_FUNCTION);
        }
@@ -2151,7 +2151,7 @@ RelationCacheInitialize(void)
        MemSet(&ctl, 0, sizeof(ctl));
        ctl.keysize = sizeof(Oid);
        ctl.entrysize = sizeof(RelIdCacheEnt);
-       ctl.hash = tag_hash;
+       ctl.hash = oid_hash;
        RelationIdCache = hash_create("Relcache by OID", INITRELCACHESIZE,
                                                                  &ctl, HASH_ELEM | HASH_FUNCTION);
 

diff --git a/src/backend/utils/cache/typcache.c b/src/backend/utils/cache/typcache.c
index 01990db..a462676 100644 (file)
--- a/src/backend/utils/cache/typcache.c
+++ b/src/backend/utils/cache/typcache.c
@@ -36,7 +36,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/cache/typcache.c,v 1.12 2005/04/14 20:03:26 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/cache/typcache.c,v 1.13 2005/04/14 20:32:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -123,7 +123,7 @@ lookup_type_cache(Oid type_id, int flags)
                MemSet(&ctl, 0, sizeof(ctl));
                ctl.keysize = sizeof(Oid);
                ctl.entrysize = sizeof(TypeCacheEntry);
-               ctl.hash = tag_hash;
+               ctl.hash = oid_hash;
                TypeCacheHash = hash_create("Type information cache", 64,
                                                                        &ctl, HASH_ELEM | HASH_FUNCTION);
        }

diff --git a/src/backend/utils/fmgr/fmgr.c b/src/backend/utils/fmgr/fmgr.c
index 0e9716d..181da00 100644 (file)
--- a/src/backend/utils/fmgr/fmgr.c
+++ b/src/backend/utils/fmgr/fmgr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/fmgr/fmgr.c,v 1.93 2005/03/31 22:46:16 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/fmgr/fmgr.c,v 1.94 2005/04/14 20:32:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -509,7 +509,7 @@ record_C_func(HeapTuple procedureTuple,
                MemSet(&hash_ctl, 0, sizeof(hash_ctl));
                hash_ctl.keysize = sizeof(Oid);
                hash_ctl.entrysize = sizeof(CFuncHashTabEntry);
-               hash_ctl.hash = tag_hash;
+               hash_ctl.hash = oid_hash;
                CFuncHash = hash_create("CFuncHash",
                                                                100,
                                                                &hash_ctl,

diff --git a/src/backend/utils/hash/hashfn.c b/src/backend/utils/hash/hashfn.c
index c27417d..24255f3 100644 (file)
--- a/src/backend/utils/hash/hashfn.c
+++ b/src/backend/utils/hash/hashfn.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/hash/hashfn.c,v 1.22 2004/12/31 22:01:37 pgsql Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/hash/hashfn.c,v 1.23 2005/04/14 20:32:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -40,3 +40,16 @@ tag_hash(const void *key, Size keysize)
        return DatumGetUInt32(hash_any((const unsigned char *) key,
                                                                   (int) keysize));
 }
+
+/*
+ * oid_hash: hash function for keys that are OIDs
+ *
+ * (tag_hash works for this case too, but is slower)
+ */
+uint32
+oid_hash(const void *key, Size keysize)
+{
+       Assert(keysize == sizeof(Oid));
+       /* We don't actually bother to do anything to the OID value ... */
+       return (uint32) *((const Oid *) key);
+}

diff --git a/src/include/utils/hsearch.h b/src/include/utils/hsearch.h
index 9773dc7..e6293bc 100644 (file)
--- a/src/include/utils/hsearch.h
+++ b/src/include/utils/hsearch.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/hsearch.h,v 1.34 2004/12/31 22:03:46 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/utils/hsearch.h,v 1.35 2005/04/14 20:32:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -184,5 +184,6 @@ extern long hash_select_dirsize(long num_entries);
  */
 extern uint32 string_hash(const void *key, Size keysize);
 extern uint32 tag_hash(const void *key, Size keysize);
+extern uint32 oid_hash(const void *key, Size keysize);
 
 #endif   /* HSEARCH_H */