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 85e125c..0efc4af 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);
                        }
                }
        }