Horton
Menu

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

Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>

View thread
From: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.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: 2022-12-07T13:13:13Z
Lists: pgsql-hackers 
On Wednesday, December 7, 2022 7:51 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> 
> On Mon, Dec 5, 2022 at 1:29 PM houzj.fnst@fujitsu.com
> <houzj.fnst@fujitsu.com> wrote:
> >
> > On Sunday, December 4, 2022 7:17 PM houzj.fnst@fujitsu.com
> <houzj.fnst@fujitsu.com>
> > >
> > > Thursday, December 1, 2022 8:40 PM Amit Kapila
> <amit.kapila16@gmail.com>
> > > wrote:
> > > > Some other comments:
> > > ...
> > > Attach the new version patch set which addressed most of the comments
> > > received so far except some comments being discussed[1].
> > > [1]
> https://www.postgresql.org/message-id/OS0PR01MB57167BF64FC0891734C
> 8E81A94149%40OS0PR01MB5716.jpnprd01.prod.outlook.com
> >
> > Attach a new version patch set which fixed a testcase failure on CFbot.
> 
> ---
> If a value of max_parallel_apply_workers_per_subscription is not
> sufficient, we get the LOG "out of parallel apply workers" every time
> when the apply worker doesn't launch a worker. But do we really need
> this log? It seems not consistent with
> max_sync_workers_per_subscription behavior. I think we can check if
> the number of running parallel workers is less than
> max_parallel_apply_workers_per_subscription before calling
> logicalrep_worker_launch(). What do you think?

(Sorry, I missed this comment in last email)

I personally feel giving a hint might help user to realize that the
max_parallel_applyxxx is not enough for the current workload and then they can
adjust the parameter. Otherwise, user might have an easy way to check if more
workers are needed.

Best regards,
Hou zj

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.