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 5654c13d4f36356519c63177581e910bb3d05b17..8d2490208d447f1b1498e20b37586bb7d9f49686 100644 (file)
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -3741,6 +3741,15 @@ 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
@@ -3762,7 +3771,6 @@ 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;
        }