Horton

Re: Race condition in recovery?

Kyotaro Horiguchi <horikyota.ntt@gmail.com>

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From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
To: dilipbalaut@gmail.com
Cc: robertmhaas@gmail.com, pgsql-hackers@lists.postgresql.org, hlinnaka@iki.fi
Date: 2021-05-27T07:37:41Z
Lists: pgsql-hackers 
At Thu, 27 May 2021 12:47:30 +0530, Dilip Kumar <dilipbalaut@gmail.com> wrote in 
> On Thu, May 27, 2021 at 12:09 PM Kyotaro Horiguchi
> <horikyota.ntt@gmail.com> wrote:
> >
> > At Thu, 27 May 2021 11:44:47 +0530, Dilip Kumar <dilipbalaut@gmail.com> wrote in
> > We're writing at the very beginning of the switching segment at the
> > promotion time. So it is guaranteed that the first segment of the
> > newer timline won't be archived until the rest almost 16MB in the
> > segment is consumed or someone explicitly causes a segment switch
> > (including archive timeout).
> 
> I agree
>
> > > BTW, I have also tested your script and I found below log, which shows
> > > that standby2 is successfully able to select the timeline2 so it is
> > > not reproducing the issue.  Am I missing something?
> >
> > standby_2? My last one 026_timeline_issue_2.pl doesn't use that name
> > and uses "standby_1 and "cascade".  In the ealier ones, standby_4 and
> > 5 (or 3 and 4 in the later versions) are used in ths additional tests.
> >
> > So I think it shold be something different?
> 
> Yeah, I tested with your patch where you had a different test case,
> with "026_timeline_issue_2.pl", I am able to reproduce the issue.

That said, I don't object if we decide to choose the crafted archive
command as far as we consider the trade-offs between the two ways.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

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.