Fix EXPLAIN so that it can drill down through multiple levels of subplan

when trying to locate the referent of a RECORD variable.  This fixes the
'record type has not been registered' failure reported by Stefan
Kaltenbrunner about a month ago.  A side effect of the way I chose to
fix it is that most variable references in join conditions will now be
properly labeled with the variable's source table name, instead of the
not-too-helpful 'outer' or 'inner' we used to use.

1 files changed, 15 insertions, 26 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index e6492720b6a..9c71cfeea89 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994-5, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.146 2006/03/05 15:58:24 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.147 2006/04/08 18:49:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -58,7 +58,7 @@ static void show_upper_qual(List *qual, const char *qlabel,
 				const char *outer_name, int outer_varno, Plan *outer_plan,
 				const char *inner_name, int inner_varno, Plan *inner_plan,
 				StringInfo str, int indent, ExplainState *es);
-static void show_sort_keys(List *tlist, int nkeys, AttrNumber *keycols,
+static void show_sort_keys(Plan *sortplan, int nkeys, AttrNumber *keycols,
 			   const char *qlabel,
 			   StringInfo str, int indent, ExplainState *es);
 
@@ -815,7 +815,7 @@ explain_outNode(StringInfo str,
 							str, indent, es);
 			break;
 		case T_Sort:
-			show_sort_keys(plan->targetlist,
+			show_sort_keys(plan,
 						   ((Sort *) plan)->numCols,
 						   ((Sort *) plan)->sortColIdx,
 						   "Sort Key",
@@ -1030,8 +1030,6 @@ show_scan_qual(List *qual, const char *qlabel,
 			   int scanrelid, Plan *outer_plan,
 			   StringInfo str, int indent, ExplainState *es)
 {
-	RangeTblEntry *rte;
-	Node	   *scancontext;
 	Node	   *outercontext;
 	List	   *context;
 	Node	   *node;
@@ -1045,11 +1043,6 @@ show_scan_qual(List *qual, const char *qlabel,
 	/* Convert AND list to explicit AND */
 	node = (Node *) make_ands_explicit(qual);
 
-	/* Generate deparse context */
-	Assert(scanrelid > 0 && scanrelid <= list_length(es->rtable));
-	rte = rt_fetch(scanrelid, es->rtable);
-	scancontext = deparse_context_for_rte(rte);
-
 	/*
 	 * If we have an outer plan that is referenced by the qual, add it to the
 	 * deparse context.  If not, don't (so that we don't force prefixes
@@ -1061,8 +1054,7 @@ show_scan_qual(List *qual, const char *qlabel,
 
 		if (bms_is_member(OUTER, varnos))
 			outercontext = deparse_context_for_subplan("outer",
-													   outer_plan->targetlist,
-													   es->rtable);
+													   (Node *) outer_plan);
 		else
 			outercontext = NULL;
 		bms_free(varnos);
@@ -1070,9 +1062,9 @@ show_scan_qual(List *qual, const char *qlabel,
 	else
 		outercontext = NULL;
 
-	context = deparse_context_for_plan(scanrelid, scancontext,
-									   OUTER, outercontext,
-									   NIL);
+	context = deparse_context_for_plan(OUTER, outercontext,
+									   0, NULL,
+									   es->rtable);
 
 	/* Deparse the expression */
 	exprstr = deparse_expression(node, context, (outercontext != NULL), false);
@@ -1106,19 +1098,17 @@ show_upper_qual(List *qual, const char *qlabel,
 	/* Generate deparse context */
 	if (outer_plan)
 		outercontext = deparse_context_for_subplan(outer_name,
-												   outer_plan->targetlist,
-												   es->rtable);
+												   (Node *) outer_plan);
 	else
 		outercontext = NULL;
 	if (inner_plan)
 		innercontext = deparse_context_for_subplan(inner_name,
-												   inner_plan->targetlist,
-												   es->rtable);
+												   (Node *) inner_plan);
 	else
 		innercontext = NULL;
 	context = deparse_context_for_plan(outer_varno, outercontext,
 									   inner_varno, innercontext,
-									   NIL);
+									   es->rtable);
 
 	/* Deparse the expression */
 	node = (Node *) make_ands_explicit(qual);
@@ -1134,7 +1124,7 @@ show_upper_qual(List *qual, const char *qlabel,
  * Show the sort keys for a Sort node.
  */
 static void
-show_sort_keys(List *tlist, int nkeys, AttrNumber *keycols,
+show_sort_keys(Plan *sortplan, int nkeys, AttrNumber *keycols,
 			   const char *qlabel,
 			   StringInfo str, int indent, ExplainState *es)
 {
@@ -1159,17 +1149,16 @@ show_sort_keys(List *tlist, int nkeys, AttrNumber *keycols,
 	 * looking at a dummy tlist generated by prepunion.c; if there are Vars
 	 * with zero varno, use the tlist itself to determine their names.
 	 */
-	varnos = pull_varnos((Node *) tlist);
+	varnos = pull_varnos((Node *) sortplan->targetlist);
 	if (bms_is_member(0, varnos))
 	{
 		Node	   *outercontext;
 
 		outercontext = deparse_context_for_subplan("sort",
-												   tlist,
-												   es->rtable);
+												   (Node *) sortplan);
 		context = deparse_context_for_plan(0, outercontext,
 										   0, NULL,
-										   NIL);
+										   es->rtable);
 		useprefix = false;
 	}
 	else
@@ -1185,7 +1174,7 @@ show_sort_keys(List *tlist, int nkeys, AttrNumber *keycols,
 	{
 		/* find key expression in tlist */
 		AttrNumber	keyresno = keycols[keyno];
-		TargetEntry *target = get_tle_by_resno(tlist, keyresno);
+		TargetEntry *target = get_tle_by_resno(sortplan->targetlist, keyresno);
 
 		if (!target)
 			elog(ERROR, "no tlist entry for key %d", keyresno);