Use only one hash entry for all instances of a pltcl trigger function.

Like plperl and unlike plpgsql, there isn't any cached state that could
depend on exactly which relation the trigger is being fired for.  So we
can use just one hash entry for all relations, which might save a little
something.

Alex Hunsaker

src/pl/tcl/pltcl.c

@@ -137,7 +137,7 @@ typedef struct pltcl_query_desc
 
 /**********************************************************************
  * For speedy lookup, we maintain a hash table mapping from
- * function OID + trigger OID + user OID to pltcl_proc_desc pointers.
+ * function OID + trigger flag + user OID to pltcl_proc_desc pointers.
  * The reason the pltcl_proc_desc struct isn't directly part of the hash
  * entry is to simplify recovery from errors during compile_pltcl_function.
  *
@@ -149,7 +149,11 @@ typedef struct pltcl_query_desc
 typedef struct pltcl_proc_key
 {
 	Oid			proc_id;				/* Function OID */
-	Oid			trig_id;				/* Trigger OID, or 0 if not trigger */
+	/*
+	 * is_trigger is really a bool, but declare as Oid to ensure this struct
+	 * contains no padding
+	 */
+	Oid			is_trigger;				/* is it a trigger function? */
 	Oid			user_id;				/* User calling the function, or 0 */
 } pltcl_proc_key;
 
@@ -1172,7 +1176,7 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid, bool pltrusted)
 
 	/* Try to find function in pltcl_proc_htab */
 	proc_key.proc_id = fn_oid;
-	proc_key.trig_id = tgreloid;
+	proc_key.is_trigger = OidIsValid(tgreloid);
 	proc_key.user_id = pltrusted ? GetUserId() : InvalidOid;
 
 	proc_ptr = hash_search(pltcl_proc_htab, &proc_key,
@@ -1228,14 +1232,16 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid, bool pltrusted)
 		int			tcl_rc;
 
 		/************************************************************
-		 * Build our internal proc name from the functions Oid + trigger Oid
+		 * Build our internal proc name from the function's Oid.  Append
+		 * "_trigger" when appropriate to ensure the normal and trigger
+		 * cases are kept separate.
 		 ************************************************************/
 		if (!is_trigger)
 			snprintf(internal_proname, sizeof(internal_proname),
 					 "__PLTcl_proc_%u", fn_oid);
 		else
 			snprintf(internal_proname, sizeof(internal_proname),
-					 "__PLTcl_proc_%u_trigger_%u", fn_oid, tgreloid);
+					 "__PLTcl_proc_%u_trigger", fn_oid);
 
 		/************************************************************
 		 * Allocate a new procedure description block