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

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

To: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>

Cc: Peter Smith <smithpb2250@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>, Dilip Kumar <dilipbalaut@gmail.com>, "shiy.fnst@fujitsu.com" <shiy.fnst@fujitsu.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2022-12-05T09:23:56Z

Lists: pgsql-hackers

On Sun, Dec 4, 2022 at 4:48 PM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
> On Friday, December 2, 2022 4:59 PM Peter Smith <smithpb2250@gmail.com> wrote:
> >
>
> > ~~~
> >
> > 12. pa_clean_subtrans
> >
> > +/* Reset the list that maintains subtransactions. */ void
> > +pa_clean_subtrans(void)
> > +{
> > + subxactlist = NIL;
> > +}
> >
> > Maybe a more informative function name would be pa_reset_subxactlist()?
>
> I thought the current name is more consistent with pa_start_subtrans.
>

Then how about changing the name to pg_reset_subtrans()?

>
> >
> > 21. apply_worker_clean_exit
> >
> > I wasn't sure if calling this a 'clean' exit meant anything much.
> >
> > How about:
> > - apply_worker_proc_exit, or
> > - apply_worker_exit
>
> I thought the clean means the exit number is 0(proc_exit(0)) and is
> not due to any ERROR, I am not sure If proc_exit or exit is better.
>
> I have addressed other comments in the new version patch.
>

+1 for apply_worker_exit.

One minor suggestion for a recent change in v56-0001*:
 /*
- * A hash table used to cache streaming transactions being applied and the
- * parallel application workers required to apply transactions.
+ * A hash table used to cache the state of streaming transactions being
+ * applied by the parallel apply workers.
  */
 static HTAB *ParallelApplyTxnHash = NULL;

-- 
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 →

Fix invalid memory access during the shutdown of the parallel apply worker.
- 3d144c6c8602 16.0 landed
Fix assertion failure in apply worker.
- de63f8dadee4 16.0 landed
Use elog to report unexpected action in handle_streamed_transaction().
- 781ac42d43ab 16.0 landed
Use appropriate wait event when sending data in the apply worker.
- d9d7fe68d35e 16.0 landed
Allow the logical_replication_mode to be used on the subscriber.
- 9f2213a7c575 16.0 landed
Rename GUC logical_decoding_mode to logical_replication_mode.
- 1e8b61735cfb 16.0 landed
Display the leader apply worker's PID for parallel apply workers.
- d540a02a724b 16.0 landed
Improve the code to decide and process the apply action.
- c981d9145dea 16.0 landed
Document the newly added wait events added by commit 216a784829.
- cd06ccd78fcf 16.0 landed
Perform apply of large transactions by parallel workers.
- 216a784829c2 16.0 landed
Wake up a subscription's replication worker processes after DDL.
- c6e1f62e2cee 16.0 cited
Add copyright notices to meson files
- 8284cf5f746f 16.0 cited
Better document logical replication parameters
- a8500750ca0a 16.0 cited
Add a common function to generate the origin name.
- 776e1c8a5d14 16.0 cited
Harmonize parameter names in storage and AM code.
- bfcf1b34805f 16.0 cited
Avoid using list_length() to test for empty list.
- efd0c16becbf 16.0 cited
Improve two comments related to a boolean DefElem's value
- 8445f5a21d40 16.0 cited
Fix partition table's REPLICA IDENTITY checking on the subscriber.
- 26b3455afaa9 15.0 cited
Fix data inconsistency between publisher and subscriber.
- b7658c24c7c1 15.0 cited
Fix cache look-up failures while applying changes in logical replication.
- 5a97b1325453 15.0 cited