Minor code rearrangement to save a few cycles in RI_FKey_check when

the subject tuple is already deleted: we need not open the pk_rel
until after we check that.

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 8eac5b8578f1c6c5b47df876960d9ad87509572e..21ae21d95cbf6cd0d826e1812a87ec93c030065f 100644 (file)
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -17,7 +17,7 @@
  *
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.86 2006/07/14 14:52:24 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.87 2006/08/21 19:15:29 tgl Exp $
  *
  * ----------
  */
@@ -193,17 +193,11 @@ RI_FKey_check(PG_FUNCTION_ARGS)
         */
        ri_CheckTrigger(fcinfo, "RI_FKey_check", RI_TRIGTYPE_INUP);
 
-       tgnargs = trigdata->tg_trigger->tgnargs;
-       tgargs = trigdata->tg_trigger->tgargs;
-
        /*
-        * Get the relation descriptors of the FK and PK tables and the new tuple.
-        *
-        * pk_rel is opened in RowShareLock mode since that's what our eventual
-        * SELECT FOR SHARE will get on it.
+        * Get arguments.
         */
-       pk_rel = heap_open(trigdata->tg_trigger->tgconstrrelid, RowShareLock);
-       fk_rel = trigdata->tg_relation;
+       tgnargs = trigdata->tg_trigger->tgnargs;
+       tgargs = trigdata->tg_trigger->tgargs;
        if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
        {
                old_row = trigdata->tg_trigtuple;
@@ -224,10 +218,16 @@ RI_FKey_check(PG_FUNCTION_ARGS)
         */
        Assert(new_row_buf != InvalidBuffer);
        if (!HeapTupleSatisfiesItself(new_row->t_data, new_row_buf))
-       {
-               heap_close(pk_rel, RowShareLock);
                return PointerGetDatum(NULL);
-       }
+
+       /*
+        * Get the relation descriptors of the FK and PK tables.
+        *
+        * pk_rel is opened in RowShareLock mode since that's what our eventual
+        * SELECT FOR SHARE will get on it.
+        */
+       fk_rel = trigdata->tg_relation;
+       pk_rel = heap_open(trigdata->tg_trigger->tgconstrrelid, RowShareLock);
 
        /* ----------
         * SQL3 11.9 <referential constraint definition>