Re: Failed assertion clauses != NIL

> On Tue, Nov 19, 2019 at 01:50:51PM +0100, Manuel Rigger wrote:
>
> when building PostgreSQL with -enable-cassert, executing the following
> statements result in an assertion error:
>
> CREATE TABLE t0(c0 boolean, c1 boolean, c2 boolean);
> INSERT INTO t0 VALUES(FALSE, FALSE, FALSE);
> CREATE STATISTICS s0 ON c0, c2 FROM t0;
> ANALYZE;
> SELECT * FROM t0 WHERE t0.c2 OR t0.c1 OR t0.c0;

Yes, I can reproduce it too. mcv_get_match_bitmap expects that
stat_clauses will not be empty, but looks like in this situation
stat_clauses is indeed NIL. clauselist_selectivity_simple right before
actually doesn't insist on stat_clauses being non empty, probably it's
just too strict assert.