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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: Peter Smith <smithpb2250@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, shveta malik <shveta.malik@gmail.com>, "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>, "shiy.fnst@fujitsu.com" <shiy.fnst@fujitsu.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Dilip Kumar <dilipbalaut@gmail.com>
Date: 2023-01-23T03:17:18Z
Lists: pgsql-hackers 
On Fri, Jan 20, 2023 at 11:48 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> >
> > Yet another way is to use the existing parameter logical_decode_mode
> > [1]. If the value of logical_decoding_mode is 'immediate', then we can
> > immediately switch to partial serialize mode. This will eliminate the
> > dependency on timing. The one argument against using this is that it
> > won't be as clear as a separate parameter like
> > 'stream_serialize_threshold' proposed by the patch but OTOH we already
> > have a few parameters that serve a different purpose when used on the
> > subscriber. For example, 'max_replication_slots' is used to define the
> > maximum number of replication slots on the publisher and the maximum
> > number of origins on subscribers. Similarly,
> > wal_retrieve_retry_interval' is used for different purposes on
> > subscriber and standby nodes.
>
> Using the existing parameter makes sense to me. But if we use
> logical_decoding_mode also on the subscriber, as Shveta Malik also
> suggested, probably it's better to rename it so as not to confuse. For
> example, logical_replication_mode or something.
>

+1. Among the options discussed, this sounds better.

-- 
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.