Horton

Re: Skipping logical replication transactions on subscriber side

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Greg Nancarrow <gregn4422@gmail.com>
Cc: vignesh C <vignesh21@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>, Alexey Lesovsky <lesovsky@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-11-19T09:14:55Z
Lists: pgsql-hackers 
On Fri, Nov 19, 2021 at 1:22 PM Greg Nancarrow <gregn4422@gmail.com> wrote:
>
> On Fri, Nov 19, 2021 at 5:52 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > Why that Assert will hit? We seem to be always passing 'create' as
> > true so it should create a new entry. I think a similar situation can
> > happen for functions and it will be probably cleaned in the next
> > vacuum cycle.
> >
> Oops, I missed that too. So at worst, vacuum will clean it up in the
> out-of-order SUBSCRIPTIONPURGE,SUBWORKERERROR case.
>
> But I still think the current code may not correctly handle
> first_error_time/last_error_time timestamps if out-of-order
> SUBWORKERERROR messages occur, right?
>

Yeah in such a case last_error_time can be shown as a time before
first_error_time but I don't think that will be a big problem, the
next message will fix it. I don't see what we can do about it and the
same is true for other cases like pg_stat_archiver where the success
and failure times can be out of order. If we want we can remove one of
those times but I don't think this happens frequently enough to be
considered a problem. Anyway, these stats are not considered to be
updated with the most latest info.

-- 
With Regards,
Amit Kapila.

Commits

  1. Test ALIGNOF_DOUBLE==4 compatibility under ALIGNOF_DOUBLE==8.

  2. Reorder subskiplsn in pg_subscription to avoid alignment issues.

  3. Add ALTER SUBSCRIPTION ... SKIP.

  4. Optionally disable subscriptions on error.

  5. Update docs of logical replication for commit 8d74fc96db.

  6. Respect permissions within logical replication.

  7. Fix regression test failure caused by commit 8d74fc96db.

  8. Add a view to show the stats of subscription workers.

  9. Add logical change details to logical replication worker errcontext.

  10. Rename LOGICAL_REP_MSG_STREAM_END to LOGICAL_REP_MSG_STREAM_STOP.

  11. Fix typo in protocol.sgml.

  12. Remove unused argument in apply_handle_commit_internal().

  13. Fix replication of in-progress transactions in tablesync worker.

  14. Reorder pg_sequence columns to avoid alignment issue