On Wed, 2016-03-09 at 08:45 -0800, Jeff Janes wrote:
> On Wed, Mar 9, 2016 at 7:02 AM, Tomas Vondra
> <tomas.von...@2ndquadrant.com> wrote:
> > Hi,
> >
> > thanks for the feedback. Attached is v14 of the patch series, fixing
> > most of the points you've raised.
> Hi Tomas,
> Applied to aa09cd242fa7e3a694a31f, I still get the seg faults in make
> check if I configure without --enable-cassert.

Ah, after disabling asserts I can reproduce it too. And the reason why
it fails is quite simple - clauselist_selectivity modifies the original
list of clauses, which then confuses cost_qual_eval.

Can you try if the attached patch fixes the issue? I'll need to rework a
bit more of the code, but let's see if this fixes the issue on your
machine too.

> With --enable-cassert, it passes the regression test.

I wonder how can it work with casserts and fail without them. That's
kinda exactly the opposite to what I'd expect ...


Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c
index 2540da9..ddfdc3b 100644
--- a/src/backend/optimizer/path/clausesel.c
+++ b/src/backend/optimizer/path/clausesel.c
@@ -279,6 +279,10 @@ clauselist_selectivity(PlannerInfo *root,
 		List *solution = choose_mv_statistics(root, relid, stats,
 											  clauses, conditions);
+		/* FIXME we must not scribble over the original list */
+		if (solution)
+			clauses = list_copy(clauses);
 		 * We have a good solution, which is merely a list of statistics that
 		 * we need to apply. We'll apply the statistics one by one (in the order
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