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

Yu Shi (Fujitsu) <shiy.fnst@fujitsu.com>

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From: "shiy.fnst@fujitsu.com" <shiy.fnst@fujitsu.com>
To: "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>, Peter Smith <smithpb2250@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-10-28T09:34:16Z
Lists: pgsql-hackers

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On Tue, Oct 25, 2022 2:56 PM Wang, Wei/王 威 <wangw.fnst@fujitsu.com> wrote:
> 
> On Tues, Oct 25, 2022 at 14:28 PM Peter Smith <smithpb2250@gmail.com>
> wrote:
> > FYI - After a recent push, the v40-0001 patch no longer applies on the
> > latest HEAD.
> >
> > [postgres@CentOS7-x64 oss_postgres_misc]$ git apply
> > ../patches_misc/v40-0001-Perform-streaming-logical-transactions-by-
> > parall.patch
> > error: patch failed: src/backend/replication/logical/launcher.c:54
> > error: src/backend/replication/logical/launcher.c: patch does not apply
> 
> Thanks for your reminder.
> 
> I just rebased the patch set for review.
> The new patch set will be shared later when the comments in this thread are
> addressed.
> 

I tried to write a draft patch to force streaming every change instead of
waiting until logical_decoding_work_mem is exceeded, which could help to test
streaming parallel. Attach the patch. This is based on v41-0001 patch.

With this patch, I saw a problem that the subscription option "origin" doesn't
work when using streaming parallel. That's because when the parallel apply
worker writing the WAL for the changes, replorigin_session_origin is
InvalidRepOriginId. In current patch, origin can be active only in one process
at-a-time.

To fix it, maybe we need to remove this restriction, like what we did in the old
version of patch.

Regards
Shi yu

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.