Re: Flaky vacuum truncate test in reloptions.sql

Arseny Sher <a.sher@postgrespro.ru>

From: Arseny Sher <a.sher@postgrespro.ru>
To: Michael Paquier <michael@paquier.xyz>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-03-30T13:22:18Z
Lists: pgsql-hackers
On 3/30/21 10:12 AM, Michael Paquier wrote:

 > Yep, this is the same problem as the one discussed for c2dc1a7, where
 > a concurrent checkpoint may cause a page to be skipped, breaking the
 > test.

Indeed, Alexander Lakhin pointed me to that commit after I wrote the 
message.

 > Why not just using DISABLE_PAGE_SKIPPING instead here?

I think this is not enough. DISABLE_PAGE_SKIPPING disables vm consulting 
(sets
aggressive=true in the routine); however, if the page is locked and
lazy_check_needs_freeze says there is nothing to freeze on it, we again 
don't
look at its contents closely.


-- cheers, arseny



Commits

  1. Improve stability of test with vacuum_truncate in reloptions.sql