Re: Make default subscription streaming option as Parallel
Amit Kapila <amit.kapila16@gmail.com>
From: Amit Kapila <amit.kapila16@gmail.com>
To: Peter Smith <smithpb2250@gmail.com>
Cc: vignesh C <vignesh21@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-10-23T03:52:38Z
Lists: pgsql-hackers
On Wed, Oct 23, 2024 at 5:58 AM Peter Smith <smithpb2250@gmail.com> wrote: > > Hi Vignesh, here are some review comments for the patch v5-0001 (docs only). > > ====== > Commit message > > 1. > The commit message only refers to this as the "streaming option", but > an option of what? Somewhere we should mention this is an option of > CREATE SUBSCRIPTION. > I think we can change the first line to: "Previously the default value of streaming option for a subscription was 'off'...." > > ====== > doc/src/sgml/ref/create_subscription.sgml > > 3. > <para> > Specifies whether to enable streaming of in-progress transactions > - for this subscription. The default value is <literal>off</literal>, > - meaning all transactions are fully decoded on the publisher and only > - then sent to the subscriber as a whole. > + for this subscription. The default value is > <literal>parallel</literal>, > + meaning incoming changes are directly applied via one of the parallel > + apply workers, if available. If no parallel apply worker is free to > + handle streaming transactions then the changes are written to > + temporary files and applied after the transaction is committed. Note > + that if an error happens in a parallel apply worker, the finish LSN > + of the remote transaction might not be reported in the server log. > </para> > > The other enum values have separate paragraphs: > - "If set to 'on'" and > - "If set to 'off'" > > I felt the 'parallel' value description should have this same style -- > e.g. a separate paragraph saying: > - "If set to 'parallel' (the default value)...". > > IMO, doing this makes the 3 available enum values much clearer. > The currently proposed way is better as it maintains the description flow. With your proposal, there is some repetition and it is not making things significantly better. This is a matter of opinion, so I leave it to others to see if they have any opinions. -- With Regards, Amit Kapila.
Commits
-
Change the default value of the streaming option to 'parallel'.
- 1bf1140be872 18.0 landed