Horton

Re: Race condition in recovery?

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, hlinnaka <hlinnaka@iki.fi>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-05-21T16:52:54Z
Lists: pgsql-hackers 
On Thu, May 20, 2021 at 10:21 PM Kyotaro Horiguchi
<horikyota.ntt@gmail.com> wrote:
> > > Conclusion:
> > > - I think now we agree on the point that initializing expectedTLEs
> > > with the recovery target timeline is the right fix.
> > > - We still have some differences of opinion about what was the
> > > original problem in the base code which was fixed by the commit
> > > (ee994272ca50f70b53074f0febaec97e28f83c4e).
> >
> > I am also still concerned about whether we understand in exactly what
> > cases the current logic doesn't work. We seem to more or less agree on
> > the fix, but I don't think we really understand precisely what case we
> > are fixing.
>
> Does the discussion above make sense?

I had trouble following it completely, but I didn't really spot
anything that seemed definitely wrong. However, I don't understand
what it has to do with where we are now. What I want to understand is:
under exactly what circumstances does it matter that
WaitForWALToBecomeAvailable(), when currentSource == XLOG_FROM_STREAM,
will stream from receiveTLI rather than recoveryTargetTLI?

-- 
Robert Haas
EDB: http://www.enterprisedb.com

Commits

  1. Further refinement of stuck_on_old_timeline recovery test

  2. Adjust new test case to set wal_keep_segments.

  3. Adjust new test case to set wal_keep_size.

  4. Fix corner case failure of new standby to follow new primary.

  5. Back-port a few PostgresNode.pm methods.

  6. Allow PostgresNode.pm's backup method to accept backup_options.

  7. Add end-to-end testing of pg_basebackup's tar-format output.

  8. Allow PostgresNode.pm tests to wait for catchup

  9. Delay reading timeline history file until it's fetched from master.