This patch moves some code for preprocessing FOR UPDATE from

Neil Conway · Neil Conway · commit d344505d1bba · 2005-03-17T23:45:09.000Z
grouping_planner() to preprocess_targetlist(), according to a comment
in grouping_planner(). I think the refactoring makes sense, and moves
some extraneous details out of grouping_planner().
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.179 2005/03/10 23:21:22 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.180 2005/03/17 23:44:26 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -36,7 +36,6 @@
 #include "optimizer/subselect.h"
 #include "optimizer/tlist.h"
 #include "optimizer/var.h"
-#include "parser/analyze.h"
 #include "parser/parsetree.h"
 #include "parser/parse_expr.h"
 #include "parser/parse_oper.h"
@@ -698,65 +697,8 @@ grouping_planner(Query *parse, double tuple_fraction)
 
 		MemSet(&agg_counts, 0, sizeof(AggClauseCounts));
 
-		/* Preprocess targetlist in case we are inside an INSERT/UPDATE. */
-		tlist = preprocess_targetlist(tlist,
-									  parse->commandType,
-									  parse->resultRelation,
-									  parse->rtable);
-
-		/*
-		 * Add TID targets for rels selected FOR UPDATE (should this be
-		 * done in preprocess_targetlist?).  The executor uses the TID to
-		 * know which rows to lock, much as for UPDATE or DELETE.
-		 */
-		if (parse->rowMarks)
-		{
-			ListCell   *l;
-
-			/*
-			 * We've got trouble if the FOR UPDATE appears inside
-			 * grouping, since grouping renders a reference to individual
-			 * tuple CTIDs invalid.  This is also checked at parse time,
-			 * but that's insufficient because of rule substitution, query
-			 * pullup, etc.
-			 */
-			CheckSelectForUpdate(parse);
-
-			/*
-			 * Currently the executor only supports FOR UPDATE at top
-			 * level
-			 */
-			if (PlannerQueryLevel > 1)
-				ereport(ERROR,
-						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-						 errmsg("SELECT FOR UPDATE is not allowed in subqueries")));
-
-			foreach(l, parse->rowMarks)
-			{
-				Index		rti = lfirst_int(l);
-				char	   *resname;
-				Resdom	   *resdom;
-				Var		   *var;
-				TargetEntry *ctid;
-
-				resname = (char *) palloc(32);
-				snprintf(resname, 32, "ctid%u", rti);
-				resdom = makeResdom(list_length(tlist) + 1,
-									TIDOID,
-									-1,
-									resname,
-									true);
-
-				var = makeVar(rti,
-							  SelfItemPointerAttributeNumber,
-							  TIDOID,
-							  -1,
-							  0);
-
-				ctid = makeTargetEntry(resdom, (Expr *) var);
-				tlist = lappend(tlist, ctid);
-			}
-		}
+		/* Preprocess targetlist */
+		tlist = preprocess_targetlist(parse, tlist);
 
 		/*
 		 * Generate appropriate target list for subplan; may be different
diff --git a/src/backend/optimizer/prep/preptlist.c b/src/backend/optimizer/prep/preptlist.c
@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.72 2004/12/31 22:00:20 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.73 2005/03/17 23:44:52 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -26,6 +26,8 @@
 #include "catalog/pg_type.h"
 #include "nodes/makefuncs.h"
 #include "optimizer/prep.h"
+#include "optimizer/subselect.h"
+#include "parser/analyze.h"
 #include "parser/parsetree.h"
 #include "parser/parse_coerce.h"
 
@@ -41,11 +43,12 @@ static List *expand_targetlist(List *tlist, int command_type,
  *	  Returns the new targetlist.
  */
 List *
-preprocess_targetlist(List *tlist,
-					  int command_type,
-					  Index result_relation,
-					  List *range_table)
+preprocess_targetlist(Query *parse, List *tlist)
 {
+	int		result_relation = parse->resultRelation;
+	List   *range_table = parse->rtable;
+	CmdType	command_type = parse->commandType;
+
 	/*
 	 * Sanity check: if there is a result relation, it'd better be a real
 	 * relation not a subquery.  Else parser or rewriter messed up.
@@ -99,6 +102,60 @@ preprocess_targetlist(List *tlist,
 		tlist = lappend(tlist, makeTargetEntry(resdom, (Expr *) var));
 	}
 
+	/*
+	 * Add TID targets for rels selected FOR UPDATE.  The executor
+	 * uses the TID to know which rows to lock, much as for UPDATE or
+	 * DELETE.
+	 */
+	if (parse->rowMarks)
+	{
+		ListCell   *l;
+
+		/*
+		 * We've got trouble if the FOR UPDATE appears inside
+		 * grouping, since grouping renders a reference to individual
+		 * tuple CTIDs invalid.  This is also checked at parse time,
+		 * but that's insufficient because of rule substitution, query
+		 * pullup, etc.
+		 */
+		CheckSelectForUpdate(parse);
+
+		/*
+		 * Currently the executor only supports FOR UPDATE at top
+		 * level
+		 */
+		if (PlannerQueryLevel > 1)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("SELECT FOR UPDATE is not allowed in subqueries")));
+
+		foreach(l, parse->rowMarks)
+		{
+			Index		rti = lfirst_int(l);
+			char	   *resname;
+			Resdom	   *resdom;
+			Var		   *var;
+			TargetEntry *ctid;
+
+			resname = (char *) palloc(32);
+			snprintf(resname, 32, "ctid%u", rti);
+			resdom = makeResdom(list_length(tlist) + 1,
+								TIDOID,
+								-1,
+								resname,
+								true);
+
+			var = makeVar(rti,
+						  SelfItemPointerAttributeNumber,
+						  TIDOID,
+						  -1,
+						  0);
+
+			ctid = makeTargetEntry(resdom, (Expr *) var);
+			tlist = lappend(tlist, ctid);
+		}
+	}
+
 	return tlist;
 }
 
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/prep.h,v 1.47 2004/12/31 22:03:36 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/prep.h,v 1.48 2005/03/17 23:45:09 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,8 +42,7 @@ extern Node *flatten_andors(Node *node);
 /*
  * prototypes for preptlist.c
  */
-extern List *preprocess_targetlist(List *tlist, int command_type,
-					  Index result_relation, List *range_table);
+extern List *preprocess_targetlist(Query *parse, List *tlist);
 
 /*
  * prototypes for prepunion.c
