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: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-05-27T10:26:33Z
Lists: pgsql-hackers 
On Thu, May 27, 2021 at 12:01 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> On Wed, May 26, 2021 at 6:11 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > I agree with you that specifying XID could be easier and
> > understandable for users. I was thinking and studying a bit about what
> > other systems do in this regard. Why don't we try to provide conflict
> > resolution methods for users? The idea could be that either the
> > conflicts can be resolved automatically or manually. In the case of
> > manual resolution, users can use the existing methods or the XID stuff
> > you are proposing here and in case of automatic resolution, the
> > in-built or corresponding user-defined functions will be invoked for
> > conflict resolution. There are more details to figure out in the
> > automatic resolution scheme but I see a lot of value in doing the
> > same.
>
> Yeah, I also see a lot of value in automatic conflict resolution. But
> maybe we can have both ways? For example, in case where the user wants
> to resolve conflicts in different ways or a conflict that cannot be
> resolved by automatic resolution (not sure there is in practice
> though), the manual resolution would also have value.
>

Right, that is exactly what I was saying. So, even if both can be done
as separate patches, we should try to design the manual resolution in
a way that can be extended for an automatic resolution system. I think
we can try to have some initial idea/design/POC for an automatic
resolution as well to ensure that the manual resolution scheme can be
further extended.

-- 
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