From 8f2e53bc1063f6c43d09356ecb6095be0cd907ea Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 11 May 2003 15:03:52 +0000
Subject: [PATCH] Disable the recently-added use_physical_tlist optimization in
 cases where the table contains dropped columns.  If the columns are dropped,
 then their types may be gone as well, which causes ExecTypeFromTL() to fail
 if the dropped columns appear in a plan node's tlist.  This could be worked
 around but I don't think the optimization is valuable enough to be worth the
 trouble.

---
 src/backend/optimizer/plan/createplan.c |  8 +++++++-
 src/backend/optimizer/util/plancat.c    | 20 +++++++++++++++++---
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index b491065f03..3445400988 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.139 2003/05/06 00:20:32 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.140 2003/05/11 15:03:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -296,6 +296,12 @@ use_physical_tlist(RelOptInfo *rel)
 	if (rel->reloptkind != RELOPT_BASEREL)
 		return false;
 	/*
+	 * Can't do it if relation contains dropped columns.  This is detected
+	 * in plancat.c, see notes there.
+	 */
+	if (rel->varlist == NIL)
+		return false;
+	/*
 	 * Can't do it if any system columns are requested, either.  (This could
 	 * possibly be fixed but would take some fragile assumptions in setrefs.c,
 	 * I think.)
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 029ddae189..943e5752fa 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.79 2003/02/09 06:56:27 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.80 2003/05/11 15:03:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -62,8 +62,15 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel)
 	relation = heap_open(relationObjectId, AccessShareLock);
 
 	/*
-	 * Make list of physical Vars.  Note we do NOT ignore dropped columns;
-	 * the intent is to model the physical tuples of the relation.
+	 * Make list of physical Vars.  But if there are any dropped columns,
+	 * punt and set varlist to NIL.  (XXX Ideally we would like to include
+	 * dropped columns so that the varlist models the physical tuples
+	 * of the relation.  However this creates problems for ExecTypeFromTL,
+	 * which may be asked to build a tupdesc for a tlist that includes vars
+	 * of no-longer-existent types.  In theory we could dig out the required
+	 * info from the pg_attribute entries of the relation, but that data is
+	 * not readily available to ExecTypeFromTL.  For now, punt and don't
+	 * apply the physical-tlist optimization when there are dropped cols.)
 	 */
 	numattrs = RelationGetNumberOfAttributes(relation);
 
@@ -71,6 +78,13 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel)
 	{
 		Form_pg_attribute att_tup = relation->rd_att->attrs[attrno - 1];
 
+		if (att_tup->attisdropped)
+		{
+			/* found a dropped col, so punt */
+			varlist = NIL;
+			break;
+		}
+
 		varlist = lappend(varlist,
 						  makeVar(varno,
 								  attrno,
-- 
2.11.0