From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 31 Mar 2013 22:33:01 +0000 (-0400)
Subject: Ignore extra subquery outputs in set_subquery_size_estimates().
X-Git-Tag: REL9_2_4~5
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0044f456d909b12f6bea2fff4d48fc0848b1b54b;p=postgresql

Ignore extra subquery outputs in set_subquery_size_estimates().

In commit 0f61d4dd1b4f95832dcd81c9688dac56fd6b5687, 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
index 875c611ab5..f5d76b29e6 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -3700,6 +3700,15 @@ 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
@@ -3721,7 +3730,6 @@ 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;
 	}