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Re: Perform streaming logical transactions by background workers and parallel apply

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: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>, Peter Smith <smithpb2250@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, "shiy.fnst@fujitsu.com" <shiy.fnst@fujitsu.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-12-01T08:46:10Z
Lists: pgsql-hackers 
On Thu, Dec 1, 2022 at 11:44 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> On Wed, Nov 30, 2022 at 7:54 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Tue, Nov 29, 2022 at 10:18 AM houzj.fnst@fujitsu.com
> > <houzj.fnst@fujitsu.com> wrote:
> > >
> > > Attach the new version patch which addressed all comments.
> > >
> >
> > Some comments on v53-0002*
> > ========================
> > 1. I think testing the scenario where the shm_mq buffer is full
> > between the leader and parallel apply worker would require a large
> > amount of data and then also there is no guarantee. How about having a
> > developer GUC [1] force_apply_serialize which allows us to serialize
> > the changes and only after commit the parallel apply worker would be
> > allowed to apply it?
>
> +1
>
> The code coverage report shows that we don't cover the partial
> serialization codes. This GUC would improve the code coverage.
>

Shall we keep it as a boolean or an integer? Keeping it as an integer
as suggested by Kuroda-San [1] would have an added advantage that we
can easily test the cases where serialization would be triggered after
sending some changes.

[1] - https://www.postgresql.org/message-id/TYAPR01MB5866160DE81FA2D88B8F22DEF5159%40TYAPR01MB5866.jpnprd01.prod.outlook.com

-- 
With Regards,
Amit Kapila.

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix invalid memory access during the shutdown of the parallel apply worker.

  2. Fix assertion failure in apply worker.

  3. Use elog to report unexpected action in handle_streamed_transaction().

  4. Use appropriate wait event when sending data in the apply worker.

  5. Allow the logical_replication_mode to be used on the subscriber.

  6. Rename GUC logical_decoding_mode to logical_replication_mode.

  7. Display the leader apply worker's PID for parallel apply workers.

  8. Improve the code to decide and process the apply action.

  9. Document the newly added wait events added by commit 216a784829.

  10. Perform apply of large transactions by parallel workers.

  11. Wake up a subscription's replication worker processes after DDL.

  12. Add copyright notices to meson files

  13. Better document logical replication parameters

  14. Add a common function to generate the origin name.

  15. Harmonize parameter names in storage and AM code.

  16. Avoid using list_length() to test for empty list.

  17. Improve two comments related to a boolean DefElem's value

  18. Fix partition table's REPLICA IDENTITY checking on the subscriber.

  19. Fix data inconsistency between publisher and subscriber.

  20. Fix cache look-up failures while applying changes in logical replication.