Horton

Re: BUG #15577: Query returns different results when executed multiple times

Thomas Munro <thomas.munro@enterprisedb.com>

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From: Thomas Munro <thomas.munro@enterprisedb.com>
To: Bartosz Polnik <bartoszpolnik@gmail.com>
Cc: David Rowley <david.rowley@2ndquadrant.com>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2019-01-07T12:19:32Z
Lists: pgsql-bugs 
On Mon, Jan 7, 2019 at 10:29 PM Bartosz Polnik <bartoszpolnik@gmail.com> wrote:
>
> > Can you confirm if there are concurrent changes being made to table_b
> > perhaps while the query is running?
>
> I confirm. There are no concurrent changes being made and I'm the only client connecting to that db.
>
> > Do you still get the variation with an otherwise idle database with no
> > open transactions that's just received a complete VACUUM?
>
> I executed VACUUM (FULL, ANALYZE) on all tables from the query, but I'm still getting different results.
>
> With your script, I'm always getting the same output, so it must be something else.

What do you get if you run it with SET force_parallel_mode = on?

-- 
Thomas Munro
http://www.enterprisedb.com

Commits

  1. Avoid sharing PARAM_EXEC slots between different levels of NestLoop.