On Wed, Jun 17, 2015 at 2:17 PM, Prakash Itnal <prakash074@gmail.com> wrote:
> Hi,
>
> Currently the issue is easily reproducible. Steps to reproduce:
> * Set some aggressive values for auto-vacuuming.
> * Run a heavy database update/delete/insert queries. This leads to invoking
> auto-vacuuming in quick successions.
> * Change the system time to older for eg. 1995-01-01
>
> Suddenly auto-vacuuming stops working. Even after changing system time back
> to current time, the auto-vacuuming did not resume.
>
> So the question is, "does postrges supports system time changes?".
PostgreSQL uses the system time to check whether it reached the
specific nap time to trigger the autovacuum worker.
Is it possible for you to check what autovauum launcher is doing even
after the system time is reset to current time?
I can think of a case where the "launcher_determine_sleep" function
returns a big sleep value because of system time change.
Because of that it is possible that the launcher is not generating
workers to do the vacuum. May be I am wrong.
Regards,
Hari Babu
Fujitsu Australia