Minor efficiency improvements in keeping track of trigger deferred

status.  In particular, I see no reason for deferredTriggerCheckState
to make an explicit entry to note that a particular trigger has its
default state --- that just clutters a list that should normally be
empty or very short.  I have plans to revise this module much more
heavily, but this is a simple separable improvement.

diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 85e125c231195b1a8e06a2cc6ffda1d07a698407..0efc4afb58c83244da81242a2d3a1b239ec50ef6 100644 (file)
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.170 2004/09/07 21:48:30 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.171 2004/09/08 23:47:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1772,7 +1772,7 @@ static DeferredTriggerState DeferredTriggerStateAddItem(DeferredTriggerState sta
 static bool
 deferredTriggerCheckState(Oid tgoid, int32 itemstate)
 {
-   bool        tgisdeferred;
+   DeferredTriggerState state = deferredTriggers->state;
    int         i;
 
    /*
@@ -1783,32 +1783,24 @@ deferredTriggerCheckState(Oid tgoid, int32 itemstate)
        return false;
 
    /*
-    * Lookup if we know an individual state for this trigger
+    * Check if SET CONSTRAINTS has been executed for this specific trigger.
     */
-   for (i = 0; i < deferredTriggers->state->numstates; i++)
+   for (i = 0; i < state->numstates; i++)
    {
-       if (deferredTriggers->state->trigstates[i].dts_tgoid == tgoid)
-           return deferredTriggers->state->trigstates[i].dts_tgisdeferred;
+       if (state->trigstates[i].dts_tgoid == tgoid)
+           return state->trigstates[i].dts_tgisdeferred;
    }
 
    /*
-    * No individual state known - so if the user issued a SET CONSTRAINT
-    * ALL ..., we return that instead of the triggers default state.
+    * Check if SET CONSTRAINTS ALL has been executed; if so use that.
     */
-   if (deferredTriggers->state->all_isset)
-       return deferredTriggers->state->all_isdeferred;
+   if (state->all_isset)
+       return state->all_isdeferred;
 
    /*
-    * No ALL state known either, remember the default state as the
-    * current and return that.  (XXX why do we bother making a state
-    * entry?)
+    * Otherwise return the default state for the trigger.
     */
-   tgisdeferred = ((itemstate & TRIGGER_DEFERRED_INITDEFERRED) != 0);
-   deferredTriggers->state =
-       DeferredTriggerStateAddItem(deferredTriggers->state,
-                                   tgoid, tgisdeferred);
-
-   return tgisdeferred;
+   return ((itemstate & TRIGGER_DEFERRED_INITDEFERRED) != 0);
 }
 
 
@@ -2486,8 +2478,7 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
    if (stmt->constraints == NIL)
    {
        /*
-        * Drop all per-transaction information about individual trigger
-        * states.
+        * Forget any previous SET CONSTRAINTS commands in this transaction.
         */
        deferredTriggers->state->numstates = 0;
 
@@ -2545,23 +2536,22 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
            while (HeapTupleIsValid(htup = systable_getnext(tgscan)))
            {
                Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
-               Oid         constr_oid;
 
                /*
                 * If we found some, check that they fit the deferrability
                 * but skip ON <event> RESTRICT ones, since they are
                 * silently never deferrable.
                 */
-               if (stmt->deferred && !pg_trigger->tgdeferrable &&
-                   pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_UPD &&
+               if (pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_UPD &&
                    pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_DEL)
-                   ereport(ERROR,
-                           (errcode(ERRCODE_WRONG_OBJECT_TYPE),
-                            errmsg("constraint \"%s\" is not deferrable",
-                                   cname)));
-
-               constr_oid = HeapTupleGetOid(htup);
-               oidlist = lappend_oid(oidlist, constr_oid);
+               {
+                   if (stmt->deferred && !pg_trigger->tgdeferrable)
+                       ereport(ERROR,
+                               (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+                                errmsg("constraint \"%s\" is not deferrable",
+                                       cname)));
+                   oidlist = lappend_oid(oidlist, HeapTupleGetOid(htup));
+               }
                found = true;
            }
 
@@ -2573,7 +2563,8 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
            if (!found)
                ereport(ERROR,
                        (errcode(ERRCODE_UNDEFINED_OBJECT),
-                    errmsg("constraint \"%s\" does not exist", cname)));
+                        errmsg("constraint \"%s\" does not exist",
+                               cname)));
        }
        heap_close(tgrel, AccessShareLock);
 
@@ -2584,14 +2575,15 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
        foreach(l, oidlist)
        {
            Oid         tgoid = lfirst_oid(l);
+           DeferredTriggerState state = deferredTriggers->state;
            bool        found = false;
            int         i;
 
-           for (i = 0; i < deferredTriggers->state->numstates; i++)
+           for (i = 0; i < state->numstates; i++)
            {
-               if (deferredTriggers->state->trigstates[i].dts_tgoid == tgoid)
+               if (state->trigstates[i].dts_tgoid == tgoid)
                {
-                   deferredTriggers->state->trigstates[i].dts_tgisdeferred = stmt->deferred;
+                   state->trigstates[i].dts_tgisdeferred = stmt->deferred;
                    found = true;
                    break;
                }
@@ -2599,8 +2591,7 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
            if (!found)
            {
                deferredTriggers->state =
-                   DeferredTriggerStateAddItem(deferredTriggers->state,
-                                               tgoid, stmt->deferred);
+                   DeferredTriggerStateAddItem(state, tgoid, stmt->deferred);
            }
        }
    }