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

Peter Smith <smithpb2250@gmail.com>

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From: Peter Smith <smithpb2250@gmail.com>
To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-12-02T21:43:15Z
Lists: pgsql-hackers 
---------- Forwarded message ---------
From: Peter Smith <smithpb2250@gmail.com>
Date: Sat, Dec 3, 2022 at 8:03 AM
Subject: Re: Perform streaming logical transactions by background
workers and parallel apply
To: Amit Kapila <amit.kapila16@gmail.com>


On Fri, Dec 2, 2022 at 8:57 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Fri, Dec 2, 2022 at 2:29 PM Peter Smith <smithpb2250@gmail.com> wrote:
> >
> > 3. pa_setup_dsm
> >
> > +/*
> > + * Set up a dynamic shared memory segment.
> > + *
> > + * We set up a control region that contains a fixed-size worker info
> > + * (ParallelApplyWorkerShared), a message queue, and an error queue.
> > + *
> > + * Returns true on success, false on failure.
> > + */
> > +static bool
> > +pa_setup_dsm(ParallelApplyWorkerInfo *winfo)
> >
> > IMO that's confusing to say "fixed-sized worker info" when it's
> > referring to the ParallelApplyWorkerShared structure and not the other
> > ParallelApplyWorkerInfo.
> >
> > Might be better to say:
> >
> > "a fixed-size worker info (ParallelApplyWorkerShared)" -> "a
> > fixed-size struct (ParallelApplyWorkerShared)"
> >
> > ~~~
> >
>
> I find the existing wording better than what you are proposing. We can
> remove the structure name if you think that is better but IMO, current
> wording is good.
>

Including the structure name was helpful, but "worker info" made me
wrongly think it was talking about ParallelApplyWorkerInfo (e.g.
"worker info" was too much like WorkerInfo). So any different way to
say "worker info" might avoid that confusion.

------
Kind Regards,
Peter Smith.
Fujitsu Australia

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.