Ignore extra subquery outputs in set_subquery_size_estimates().

tglsfdc · tglsfdc · commit ad480bd25308 · 2013-03-31T18:34:44.000-04:00
In commit 0f61d4d, I added code to copy up column width estimates for each column of a subquery. That code supposed that the subquery couldn't have any output columns that didn't correspond to known columns of the current query level --- which is true when a query is parsed from scratch, but the assumption fails when planning a view that depends on another view that's been redefined (adding output columns) since the upper view was made. This results in an assertion failure or even a crash, as per bug #8025 from lindebg. Remove the Assert and instead skip the column if its resno is out of the expected range.
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
@@ -3261,6 +3261,15 @@ set_subquery_size_estimates(PlannerInfo *root, RelOptInfo *rel,
 		if (te->resjunk)
 			continue;
 
+		/*
+		 * The subquery could be an expansion of a view that's had columns
+		 * added to it since the current query was parsed, so that there are
+		 * non-junk tlist columns in it that don't correspond to any column
+		 * visible at our query level.  Ignore such columns.
+		 */
+		if (te->resno < rel->min_attr || te->resno > rel->max_attr)
+			continue;
+
 		/*
 		 * XXX This currently doesn't work for subqueries containing set
 		 * operations, because the Vars in their tlists are bogus references
@@ -3282,7 +3291,6 @@ set_subquery_size_estimates(PlannerInfo *root, RelOptInfo *rel,
 
 			item_width = subrel->attr_widths[var->varattno - subrel->min_attr];
 		}
-		Assert(te->resno >= rel->min_attr && te->resno <= rel->max_attr);
 		rel->attr_widths[te->resno - rel->min_attr] = item_width;
 	}
 
