Remove the limit on the number of entries allowed in catcaches, and

remove the infrastructure needed to enforce the limit, ie, the global
LRU list of cache entries.  On small-to-middling databases this wins
because maintaining the LRU list is a waste of time.  On large databases
this wins because it's better to keep more cache entries (we assume
such users can afford to use some more per-backend memory than was
contemplated in the Berkeley-era catcache design).  This provides a
noticeable improvement in the speed of psql \d on a 10000-table
database, though it doesn't make it instantaneous.

While at it, use per-catcache settings for the number of hash buckets
per catcache, rather than the former one-size-fits-all value.  It's a
bit silly to be using the same number of hash buckets for, eg, pg_am
and pg_attribute.  The specific values I used might need some tuning,
but they seem to be in the right ballpark based on CATCACHE_STATS
results from the standard regression tests.

src/backend/utils/cache/syscache.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/syscache.c,v 1.103 2006/05/03 22:45:26 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/syscache.c,v 1.104 2006/06/15 02:08:09 tgl Exp $
  *
  * NOTES
  *	  These routines allow the parser/planner/executor to perform
@@ -55,14 +55,18 @@
 	the list sorted alphabetically and adjust the cache numbers
 	accordingly.
 
-	Add your entry to the cacheinfo[] array below.	All cache lists are
-	alphabetical, so add it in the proper place.  Specify the relation
-	OID, index OID, number of keys, and key attribute numbers.	If the
-	relation contains tuples that are associated with a particular relation
-	(for example, its attributes, rules, triggers, etc) then specify the
-	attribute number that contains the OID of the associated relation.
-	This is used by CatalogCacheFlushRelation() to remove the correct
-	tuples during a table drop or relcache invalidation event.
+	Add your entry to the cacheinfo[] array below. All cache lists are
+	alphabetical, so add it in the proper place.  Specify the relation OID,
+	index OID, number of keys, key attribute numbers, and number of hash
+	buckets.  If the relation contains tuples that are associated with a
+	particular relation (for example, its attributes, rules, triggers, etc)
+	then specify the attribute number that contains the OID of the associated
+	relation.  This is used by CatalogCacheFlushRelation() to remove the
+	correct tuples during a table drop or relcache invalidation event.
+
+	The number of hash buckets must be a power of 2.  It's reasonable to
+	set this to the number of entries that might be in the particular cache
+	in a medium-size database.
 
 	There must be a unique index underlying each syscache (ie, an index
 	whose key is the same as that of the cache).  If there is not one
@@ -90,6 +94,7 @@ struct cachedesc
 	int			reloidattr;		/* attr number of rel OID reference, or 0 */
 	int			nkeys;			/* # of keys needed for cache lookup */
 	int			key[4];			/* attribute numbers of key attrs */
+	int			nbuckets;		/* number of hash buckets for this cache */
 };
 
 static const struct cachedesc cacheinfo[] = {
@@ -102,7 +107,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		32
+	},
 	{AccessMethodRelationId,	/* AMNAME */
 		AmNameIndexId,
 		0,
@@ -112,7 +119,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		4
+	},
 	{AccessMethodRelationId,	/* AMOID */
 		AmOidIndexId,
 		0,
@@ -122,7 +131,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		4
+	},
 	{AccessMethodOperatorRelationId,	/* AMOPOPID */
 		AccessMethodOperatorIndexId,
 		0,
@@ -132,7 +143,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_amop_amopclaid,
 			0,
 			0
-	}},
+		},
+		64
+	},
 	{AccessMethodOperatorRelationId,	/* AMOPSTRATEGY */
 		AccessMethodStrategyIndexId,
 		0,
@@ -142,7 +155,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_amop_amopsubtype,
 			Anum_pg_amop_amopstrategy,
 			0
-	}},
+		},
+		64
+	},
 	{AccessMethodProcedureRelationId,	/* AMPROCNUM */
 		AccessMethodProcedureIndexId,
 		0,
@@ -152,7 +167,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_amproc_amprocsubtype,
 			Anum_pg_amproc_amprocnum,
 			0
-	}},
+		},
+		64
+	},
 	{AttributeRelationId,		/* ATTNAME */
 		AttributeRelidNameIndexId,
 		Anum_pg_attribute_attrelid,
@@ -162,7 +179,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_attribute_attname,
 			0,
 			0
-	}},
+		},
+		2048
+	},
 	{AttributeRelationId,		/* ATTNUM */
 		AttributeRelidNumIndexId,
 		Anum_pg_attribute_attrelid,
@@ -172,7 +191,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_attribute_attnum,
 			0,
 			0
-	}},
+		},
+		2048
+	},
 	{AuthMemRelationId,			/* AUTHMEMMEMROLE */
 		AuthMemMemRoleIndexId,
 		0,
@@ -182,7 +203,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_auth_members_roleid,
 			0,
 			0
-	}},
+		},
+		128
+	},
 	{AuthMemRelationId,			/* AUTHMEMROLEMEM */
 		AuthMemRoleMemIndexId,
 		0,
@@ -192,7 +215,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_auth_members_member,
 			0,
 			0
-	}},
+		},
+		128
+	},
 	{AuthIdRelationId,			/* AUTHNAME */
 		AuthIdRolnameIndexId,
 		0,
@@ -202,7 +227,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		128
+	},
 	{AuthIdRelationId,			/* AUTHOID */
 		AuthIdOidIndexId,
 		0,
@@ -212,7 +239,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		128
+	},
 	{
 		CastRelationId,			/* CASTSOURCETARGET */
 		CastSourceTargetIndexId,
@@ -223,7 +252,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_cast_casttarget,
 			0,
 			0
-	}},
+		},
+		256
+	},
 	{OperatorClassRelationId,	/* CLAAMNAMENSP */
 		OpclassAmNameNspIndexId,
 		0,
@@ -233,7 +264,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_opclass_opcname,
 			Anum_pg_opclass_opcnamespace,
 			0
-	}},
+		},
+		64
+	},
 	{OperatorClassRelationId,	/* CLAOID */
 		OpclassOidIndexId,
 		0,
@@ -243,7 +276,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		64
+	},
 	{ConversionRelationId,		/* CONDEFAULT */
 		ConversionDefaultIndexId,
 		0,
@@ -253,7 +288,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_conversion_conforencoding,
 			Anum_pg_conversion_contoencoding,
 			ObjectIdAttributeNumber,
-	}},
+		},
+		128
+	},
 	{ConversionRelationId,		/* CONNAMENSP */
 		ConversionNameNspIndexId,
 		0,
@@ -263,7 +300,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_conversion_connamespace,
 			0,
 			0
-	}},
+		},
+		128
+	},
 	{ConversionRelationId,		/* CONOID */
 		ConversionOidIndexId,
 		0,
@@ -273,7 +312,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		128
+	},
 	{DatabaseRelationId,		/* DATABASEOID */
 		DatabaseOidIndexId,
 		0,
@@ -283,7 +324,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		4
+	},
 	{IndexRelationId,			/* INDEXRELID */
 		IndexRelidIndexId,
 		Anum_pg_index_indrelid,
@@ -293,7 +336,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		1024
+	},
 	{InheritsRelationId,		/* INHRELID */
 		InheritsRelidSeqnoIndexId,
 		Anum_pg_inherits_inhrelid,
@@ -303,7 +348,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_inherits_inhseqno,
 			0,
 			0
-	}},
+		},
+		256
+	},
 	{LanguageRelationId,		/* LANGNAME */
 		LanguageNameIndexId,
 		0,
@@ -313,7 +360,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		4
+	},
 	{LanguageRelationId,		/* LANGOID */
 		LanguageOidIndexId,
 		0,
@@ -323,7 +372,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		4
+	},
 	{NamespaceRelationId,		/* NAMESPACENAME */
 		NamespaceNameIndexId,
 		0,
@@ -333,7 +384,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		256
+	},
 	{NamespaceRelationId,		/* NAMESPACEOID */
 		NamespaceOidIndexId,
 		0,
@@ -343,7 +396,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		256
+	},
 	{OperatorRelationId,		/* OPERNAMENSP */
 		OperatorNameNspIndexId,
 		0,
@@ -353,7 +408,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_operator_oprleft,
 			Anum_pg_operator_oprright,
 			Anum_pg_operator_oprnamespace
-	}},
+		},
+		1024
+	},
 	{OperatorRelationId,		/* OPEROID */
 		OperatorOidIndexId,
 		0,
@@ -363,7 +420,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		1024
+	},
 	{ProcedureRelationId,		/* PROCNAMEARGSNSP */
 		ProcedureNameArgsNspIndexId,
 		0,
@@ -373,7 +432,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_proc_proargtypes,
 			Anum_pg_proc_pronamespace,
 			0
-	}},
+		},
+		2048
+	},
 	{ProcedureRelationId,		/* PROCOID */
 		ProcedureOidIndexId,
 		0,
@@ -383,7 +444,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		2048
+	},
 	{RelationRelationId,		/* RELNAMENSP */
 		ClassNameNspIndexId,
 		ObjectIdAttributeNumber,
@@ -393,7 +456,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_class_relnamespace,
 			0,
 			0
-	}},
+		},
+		1024
+	},
 	{RelationRelationId,		/* RELOID */
 		ClassOidIndexId,
 		ObjectIdAttributeNumber,
@@ -403,7 +468,9 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}},
+		},
+		1024
+	},
 	{RewriteRelationId,			/* RULERELNAME */
 		RewriteRelRulenameIndexId,
 		Anum_pg_rewrite_ev_class,
@@ -413,7 +480,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_rewrite_rulename,
 			0,
 			0
-	}},
+		},
+		1024
+	},
 	{StatisticRelationId,		/* STATRELATT */
 		StatisticRelidAttnumIndexId,
 		Anum_pg_statistic_starelid,
@@ -423,7 +492,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_statistic_staattnum,
 			0,
 			0
-	}},
+		},
+		1024
+	},
 	{TypeRelationId,			/* TYPENAMENSP */
 		TypeNameNspIndexId,
 		Anum_pg_type_typrelid,
@@ -433,7 +504,9 @@ static const struct cachedesc cacheinfo[] = {
 			Anum_pg_type_typnamespace,
 			0,
 			0
-	}},
+		},
+		1024
+	},
 	{TypeRelationId,			/* TYPEOID */
 		TypeOidIndexId,
 		Anum_pg_type_typrelid,
@@ -443,11 +516,12 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0,
 			0
-	}}
+		},
+		1024
+	}
 };
 
-static CatCache *SysCache[
-						  lengthof(cacheinfo)];
+static CatCache *SysCache[lengthof(cacheinfo)];
 static int	SysCacheSize = lengthof(cacheinfo);
 static bool CacheInitialized = false;
 
@@ -476,7 +550,8 @@ InitCatalogCache(void)
 										 cacheinfo[cacheId].indoid,
 										 cacheinfo[cacheId].reloidattr,
 										 cacheinfo[cacheId].nkeys,
-										 cacheinfo[cacheId].key);
+										 cacheinfo[cacheId].key,
+										 cacheinfo[cacheId].nbuckets);
 		if (!PointerIsValid(SysCache[cacheId]))
 			elog(ERROR, "could not initialize cache %u (%d)",
 				 cacheinfo[cacheId].reloid, cacheId);

src/include/utils/catcache.h

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/catcache.h,v 1.58 2006/03/05 15:59:07 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/catcache.h,v 1.59 2006/06/15 02:08:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -60,7 +60,6 @@ typedef struct catcache
 	 * searches, each of which will result in loading a negative entry
 	 */
 	long		cc_invals;		/* # of entries invalidated from cache */
-	long		cc_discards;	/* # of entries discarded due to overflow */
 	long		cc_lsearches;	/* total # list-searches */
 	long		cc_lhits;		/* # of matches against existing lists */
 #endif
@@ -75,11 +74,10 @@ typedef struct catctup
 	CatCache   *my_cache;		/* link to owning catcache */
 
 	/*
-	 * Each tuple in a cache is a member of two Dllists: one lists all the
-	 * elements in all the caches in LRU order, and the other lists just the
-	 * elements in one hashbucket of one cache, also in LRU order.
+	 * 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		lrulist_elem;	/* list member of global LRU list */
 	Dlelem		cache_elem;		/* list member of per-bucket list */
 
 	/*
@@ -125,9 +123,8 @@ typedef struct catclist
 	 * 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 do separate
-	 * LRU management for CatCLists.  See CatalogCacheCleanup() for the
-	 * details of the management algorithm.
+	 * 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
@@ -143,7 +140,6 @@ typedef struct catclist
 	int			refcount;		/* number of active references */
 	bool		dead;			/* dead but not yet removed? */
 	bool		ordered;		/* members listed in index order? */
-	bool		touched;		/* used since last CatalogCacheCleanup? */
 	short		nkeys;			/* number of lookup keys specified */
 	uint32		hash_value;		/* hash value for lookup keys */
 	HeapTupleData tuple;		/* header for tuple holding keys */
@@ -156,8 +152,6 @@ typedef struct catcacheheader
 {
 	CatCache   *ch_caches;		/* head of list of CatCache structs */
 	int			ch_ntup;		/* # of tuples in all caches */
-	int			ch_maxtup;		/* max # of tuples allowed (LRU) */
-	Dllist		ch_lrulist;		/* overall LRU list, most recent first */
 } CatCacheHeader;
 
 
@@ -169,7 +163,8 @@ extern void AtEOXact_CatCache(bool isCommit);
 
 extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid,
 			 int reloidattr,
-			 int nkeys, const int *key);
+			 int nkeys, const int *key,
+			 int nbuckets);
 extern void InitCatCachePhase2(CatCache *cache);
 
 extern HeapTuple SearchCatCache(CatCache *cache,