88 *
99 *
1010 * IDENTIFICATION
11- * $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.211 2004/09/16 16:58:35 tgl Exp $
11+ * $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.212 2004/11/20 20:19:52 tgl Exp $
1212 *
1313 *-------------------------------------------------------------------------
1414 */
@@ -120,6 +120,11 @@ static long relcacheInvalsReceived = 0L;
120120 */
121121static List * initFileRelationIds = NIL ;
122122
123+ /*
124+ * This flag lets us optimize away work in AtEOSubXact_RelationCache().
125+ */
126+ static bool need_eosubxact_work = false;
127+
123128/*
124129 *RelationBuildDescInfo exists so code can be shared
125130 *between RelationIdGetRelation() and RelationSysNameGetRelation()
@@ -2087,6 +2092,9 @@ AtEOXact_RelationCache(bool isCommit)
20872092relation -> rd_indexvalid = 0 ;
20882093}
20892094}
2095+
2096+ /* Once done with the transaction, we can reset need_eosubxact_work */
2097+ need_eosubxact_work = false;
20902098}
20912099
20922100/*
@@ -2103,6 +2111,21 @@ AtEOSubXact_RelationCache(bool isCommit, SubTransactionId mySubid,
21032111HASH_SEQ_STATUS status ;
21042112RelIdCacheEnt * idhentry ;
21052113
2114+ /*
2115+ * In the majority of subtransactions there is not anything for this
2116+ * routine to do, and since there are usually many entries in the
2117+ * relcache, uselessly scanning the cache represents a surprisingly
2118+ * large fraction of the subtransaction entry/exit overhead. To avoid
2119+ * this, we keep a static flag that must be set whenever a condition
2120+ * is created that requires subtransaction-end work. (Currently, this
2121+ * means either a relation is created in the current xact, or an index
2122+ * list is forced.) For simplicity, the flag remains set till end of
2123+ * top-level transaction, even though we could clear it earlier in some
2124+ * cases.
2125+ */
2126+ if (!need_eosubxact_work )
2127+ return ;
2128+
21062129hash_seq_init (& status ,RelationIdCache );
21072130
21082131while ((idhentry = (RelIdCacheEnt * )hash_seq_search (& status ))!= NULL )
@@ -2184,6 +2207,9 @@ RelationBuildLocalRelation(const char *relname,
21842207/* it's being created in this transaction */
21852208rel -> rd_createSubid = GetCurrentSubTransactionId ();
21862209
2210+ /* must flag that we have rels created in this transaction */
2211+ need_eosubxact_work = true;
2212+
21872213/* is it a temporary relation? */
21882214rel -> rd_istemp = isTempNamespace (relnamespace );
21892215
@@ -2745,6 +2771,8 @@ RelationSetIndexList(Relation relation, List *indexIds)
27452771list_free (relation -> rd_indexlist );
27462772relation -> rd_indexlist = indexIds ;
27472773relation -> rd_indexvalid = 2 ;/* mark list as forced */
2774+ /* must flag that we have a forced index list */
2775+ need_eosubxact_work = true;
27482776}
27492777
27502778/*
@@ -3172,6 +3200,7 @@ load_relcache_init_file(void)
31723200rel -> rd_refcnt = 0 ;
31733201rel -> rd_indexvalid = 0 ;
31743202rel -> rd_indexlist = NIL ;
3203+ rel -> rd_createSubid = InvalidSubTransactionId ;
31753204MemSet (& rel -> pgstat_info ,0 ,sizeof (rel -> pgstat_info ));
31763205
31773206/*