Horton

Re: Skipping logical replication transactions on subscriber side

David G. Johnston <david.g.johnston@gmail.com>

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From: "David G. Johnston" <david.g.johnston@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Peter Eisentraut <peter.eisentraut@enterprisedb.com>, Amit Kapila <amit.kapila16@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, vignesh C <vignesh21@gmail.com>, Greg Nancarrow <gregn4422@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>, Alexey Lesovsky <lesovsky@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2022-01-25T15:14:00Z
Lists: pgsql-hackers 
On Tue, Jan 25, 2022 at 8:09 AM Masahiko Sawada <sawada.mshk@gmail.com>
wrote:

> On Tue, Jan 25, 2022 at 11:58 PM David G. Johnston
> <david.g.johnston@gmail.com> wrote:
> >
> > On Tue, Jan 25, 2022 at 7:47 AM Masahiko Sawada <sawada.mshk@gmail.com>
> wrote:
> >>
> >> Yeah, I think it's a good idea to clear the subskipxid after the first
> >> transaction regardless of whether the worker skipped it.
> >>
> >
> > So basically instead of stopping the worker with an error you suggest
> having the worker continue applying changes (after resetting subskipxid,
> and - arguably - the ?_error_* fields).  Log the transaction xid mis-match
> as a warning in the log file as opposed to an error.
>
> Agreed, I think it's better to log a warning than to raise an error.
> In the case where the user specified the wrong XID, the worker should
> fail again due to the same error.
>
>
If it remains possible for the system to accept a wrongly specified XID I
would agree that this behavior is preferable.  At least when the user
wonders why the skip didn't work and they are seeing the same error again
they will have a log entry warning telling them their XID choice was
incorrect.  I would prefer that the system not accept a wrongly specified
XID and the user be told directly and sooner that their XID choice was
incorrect.

David J.

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