Arrange to copy relcache's trigdesc structure at the start of any

query that uses it.  This ensures that triggers will be applied consistently
throughout a query even if someone commits changes to the relation's
pg_class.reltriggers field meanwhile.  Per crash report from Laurette Cisneros.
While at it, simplify memory management in relcache.c, which no longer
needs the old hack to try to keep trigger info in the same place over
a relcache entry rebuild.  (Should try to fix rd_att and rewrite-rule
access similarly, someday.)  And make RelationBuildTriggers simpler and
more robust by making it build the trigdesc in working memory and then
CopyTriggerDesc() into cache memory.

1 files changed, 6 insertions, 16 deletions

diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ac80fba519a..29fbd5ec067 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.176 2002/09/22 20:56:28 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.177 2002/10/14 16:51:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1716,11 +1716,11 @@ RelationClearRelation(Relation relation, bool rebuild)
 	/*
 	 * Free all the subsidiary data structures of the relcache entry. We
 	 * cannot free rd_att if we are trying to rebuild the entry, however,
-	 * because pointers to it may be cached in various places. The trigger
-	 * manager might also have pointers into the trigdesc, and the rule
-	 * manager might have pointers into the rewrite rules. So to begin
+	 * because pointers to it may be cached in various places. The rule
+	 * manager might also have pointers into the rewrite rules. So to begin
 	 * with, we can only get rid of these fields:
 	 */
+	FreeTriggerDesc(relation->trigdesc);
 	if (relation->rd_index)
 		pfree(relation->rd_index);
 	if (relation->rd_am)
@@ -1743,22 +1743,20 @@ RelationClearRelation(Relation relation, bool rebuild)
 		FreeTupleDesc(relation->rd_att);
 		if (relation->rd_rulescxt)
 			MemoryContextDelete(relation->rd_rulescxt);
-		FreeTriggerDesc(relation->trigdesc);
 		pfree(relation);
 	}
 	else
 	{
 		/*
 		 * When rebuilding an open relcache entry, must preserve ref count
-		 * and rd_isnew flag.  Also attempt to preserve the tupledesc,
-		 * rewrite rules, and trigger substructures in place.
+		 * and rd_isnew flag.  Also attempt to preserve the tupledesc and
+		 * rewrite-rule substructures in place.
 		 */
 		int			old_refcnt = relation->rd_refcnt;
 		bool		old_isnew = relation->rd_isnew;
 		TupleDesc	old_att = relation->rd_att;
 		RuleLock   *old_rules = relation->rd_rules;
 		MemoryContext old_rulescxt = relation->rd_rulescxt;
-		TriggerDesc *old_trigdesc = relation->trigdesc;
 		RelationBuildDescInfo buildinfo;
 
 		buildinfo.infotype = INFO_RELID;
@@ -1770,7 +1768,6 @@ RelationClearRelation(Relation relation, bool rebuild)
 			FreeTupleDesc(old_att);
 			if (old_rulescxt)
 				MemoryContextDelete(old_rulescxt);
-			FreeTriggerDesc(old_trigdesc);
 			pfree(relation);
 			elog(ERROR, "RelationClearRelation: relation %u deleted while still in use",
 				 buildinfo.i.info_id);
@@ -1796,13 +1793,6 @@ RelationClearRelation(Relation relation, bool rebuild)
 			if (old_rulescxt)
 				MemoryContextDelete(old_rulescxt);
 		}
-		if (equalTriggerDescs(old_trigdesc, relation->trigdesc))
-		{
-			FreeTriggerDesc(relation->trigdesc);
-			relation->trigdesc = old_trigdesc;
-		}
-		else
-			FreeTriggerDesc(old_trigdesc);
 
 		/*
 		 * Update rd_nblocks.  This is kind of expensive, but I think we