Horton
Menu

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

Amit Kapila <amit.kapila16@gmail.com>

View thread
From: Amit Kapila <amit.kapila16@gmail.com>
To: "kuroda.hayato@fujitsu.com" <kuroda.hayato@fujitsu.com>
Cc: "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Dilip Kumar <dilipbalaut@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, "shiy.fnst@fujitsu.com" <shiy.fnst@fujitsu.com>, Peter Smith <smithpb2250@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-09-23T03:47:27Z
Lists: pgsql-hackers 
On Thu, Sep 22, 2022 at 4:50 PM kuroda.hayato@fujitsu.com
<kuroda.hayato@fujitsu.com> wrote:
>
> Hi Amit,
>
> > > I checked other flags that are set by signal handlers, their datatype seemed to
> > be sig_atomic_t.
> > > Is there any reasons that you use normal bool? It should be changed if not.
> > >
> >
> > It follows the logic similar to ParallelMessagePending. Do you see any
> > problem with it?
>
> Hmm, one consideration is:
> what will happen if the signal handler HandleParallelApplyMessageInterrupt() is fired during "ParallelApplyMessagePending = false;"?
> IIUC sig_atomic_t has been needed to avoid writing to same data at the same time.
>

But we do call HOLD_INTERRUPTS() before we do
"ParallelApplyMessagePending = false;", so that should not happen.
However, I think it would be better to use sig_atomic_t here for the
sake of consistency.

I think you can start a separate thread to check if we can change
ParallelMessagePending to make it consistent with other such
variables.

-- 
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.