Re: pgsql: Attempt to fix unstable regression tests, take 2

On Wed, 1 Apr 2020 at 13:00, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> David Rowley <dgrowley@gmail.com> writes:
> > On Tue, 31 Mar 2020 at 15:55, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> Now this *IS* autovacuum interference, but it's hardly autovacuum's fault:
> >> the test script is supposing that autovac won't come in before it does a
> >> manual analyze, and that's just unsafe on its face.
>
> > Why would that matter?
>
> Look again at the failure: the problem is that the test script is
> populating a table, then doing an EXPLAIN and expecting to see
> results corresponding to a *not*-ANALYZED table, then doing ANALYZE,
> then expecting to see EXPLAIN results corresponding to the analyzed
> state.  It's the second step of that that is vulnerable to an
> ill-timed auto analyze.  The only way to prevent it is to disable
> autovac altogether on the table, as I did a little while ago
> at 0936d1b6f.

Can you share which failure you're talking about here?  All of the
ones I've looked at were failing post-ANALYZE.

David