Repair oversight in creation of "append relations": we should set up

rel->tuples as well as rel->rows, since some estimation functions expect both
to be valid in every baserel.  Per report from Dave Dutcher.

src/backend/optimizer/path/allpaths.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.157 2007/01/20 20:45:38 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.158 2007/01/28 18:50:40 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -393,6 +393,12 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
 		}
 	}
 
+	/*
+	 * Set "raw tuples" count equal to "rows" for the appendrel; needed
+	 * because some places assume rel->tuples is valid for any baserel.
+	 */
+	rel->tuples = rel->rows;
+
 	/*
 	 * Finally, build Append path and install it as the only access path for
 	 * the parent rel.	(Note: this is correct even if we have zero or one