When enqueueing after-row triggers for updates of a table with a foreign

key, compare the new and old row versions. If the foreign key column has
not changed, we needn't enqueue the trigger, since the update cannot
violate the foreign key. This optimization was previously applied in the
RI trigger function, but it is more efficient to avoid firing the trigger
altogether. Per recent discussion on pgsql-hackers.

Also add a regression test for some unintuitive foreign key behavior, and
refactor some code that deals with the OIDs of the various RI trigger
functions.

1 files changed, 2 insertions, 42 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index c54104200d7..4335792ee71 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.158 2005/05/30 06:52:38 neilc Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.159 2005/05/30 07:20:58 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -156,12 +156,6 @@ typedef struct NewColumnValue
 } NewColumnValue;
 
 
-/* Used by attribute and relation renaming routines: */
-#define RI_TRIGGER_PK	1		/* is a trigger on the PK relation */
-#define RI_TRIGGER_FK	2		/* is a trigger on the FK relation */
-#define RI_TRIGGER_NONE 0		/* is not an RI trigger function */
-
-
 static List *MergeAttributes(List *schema, List *supers, bool istemp,
 				List **supOids, List **supconstr, int *supOidCount);
 static bool change_varattnos_of_a_node(Node *node, const AttrNumber *newattno);
@@ -246,7 +240,6 @@ static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel,
 					char *tablespacename);
 static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace);
 static void copy_relation_data(Relation rel, SMgrRelation dst);
-static int	ri_trigger_type(Oid tgfoid);
 static void update_ri_trigger_args(Oid relid,
 					   const char *oldname,
 					   const char *newname,
@@ -1571,39 +1564,6 @@ renamerel(Oid myrelid, const char *newrelname)
 	relation_close(targetrelation, NoLock);
 }
 
-
-/*
- * Given a trigger function OID, determine whether it is an RI trigger,
- * and if so whether it is attached to PK or FK relation.
- *
- * XXX this probably doesn't belong here; should be exported by
- * ri_triggers.c
- */
-static int
-ri_trigger_type(Oid tgfoid)
-{
-	switch (tgfoid)
-	{
-		case F_RI_FKEY_CASCADE_DEL:
-		case F_RI_FKEY_CASCADE_UPD:
-		case F_RI_FKEY_RESTRICT_DEL:
-		case F_RI_FKEY_RESTRICT_UPD:
-		case F_RI_FKEY_SETNULL_DEL:
-		case F_RI_FKEY_SETNULL_UPD:
-		case F_RI_FKEY_SETDEFAULT_DEL:
-		case F_RI_FKEY_SETDEFAULT_UPD:
-		case F_RI_FKEY_NOACTION_DEL:
-		case F_RI_FKEY_NOACTION_UPD:
-			return RI_TRIGGER_PK;
-
-		case F_RI_FKEY_CHECK_INS:
-		case F_RI_FKEY_CHECK_UPD:
-			return RI_TRIGGER_FK;
-	}
-
-	return RI_TRIGGER_NONE;
-}
-
 /*
  * Scan pg_trigger for RI triggers that are on the specified relation
  * (if fk_scan is false) or have it as the tgconstrrel (if fk_scan
@@ -1663,7 +1623,7 @@ update_ri_trigger_args(Oid relid,
 		const char *arga[RI_MAX_ARGUMENTS];
 		const char *argp;
 
-		tg_type = ri_trigger_type(pg_trigger->tgfoid);
+		tg_type = RI_FKey_trigger_type(pg_trigger->tgfoid);
 		if (tg_type == RI_TRIGGER_NONE)
 		{
 			/* Not an RI trigger, forget it */