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

Masahiko Sawada <sawada.mshk@gmail.com>

From: Masahiko Sawada <sawada.mshk@gmail.com>
To: "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.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: 2023-01-04T05:31:25Z
Lists: pgsql-hackers
On Tue, Jan 3, 2023 at 2:40 PM wangw.fnst@fujitsu.com
<wangw.fnst@fujitsu.com> wrote:
>
> On Mon, Jan 2, 2023 at 18:54 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > On Fri, Dec 30, 2022 at 3:55 PM wangw.fnst@fujitsu.com
> > <wangw.fnst@fujitsu.com> wrote:
> > >
> > > I've checked it and it looks good to me.
> > > Rebased the other patches and ran the pgident for the patch set.
> > >
> > > Attach the new patch set.
> > >
> >
> > I have added a few DEBUG messages and changed a few comments in the
> > 0001 patch. With that v71-0001* looks good to me and I'll commit it
> > later this week (by Thursday or Friday) unless there are any major
> > comments or objections.
>
> Thanks for your improvement.
>
> Rebased the patch set because the new change in HEAD (c8e1ba7).
> Attach the new patch set.

There are some unused parameters in v72 patches:

+static bool
+pa_can_start(TransactionId xid)
+{
+        Assert(TransactionIdIsValid(xid));

'xid' is used only for the assertion check but I don't think it's necessary.

---
+/*
+ * Make sure the leader apply worker tries to read from our error
queue one more
+ * time. This guards against the case where we exit uncleanly without sending
+ * an ErrorResponse, for example because some code calls proc_exit directly.
+ */
+static void
+pa_shutdown(int code, Datum arg)

Similarly, we don't use 'code' here.

---
+/*
+ * Handle a single protocol message received from a single parallel apply
+ * worker.
+ */
+static void
+HandleParallelApplyMessage(ParallelApplyWorkerInfo *winfo, StringInfo msg)

In addition, the same is true for 'winfo'.

The rest looks good to me.

Regards,

-- 
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com



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.