I've also attached the pg_rewind optimization patch file for Postgres version 14.4. The previous patch file targets version Postgres version 15 Beta 1/2.
Thanks,
Justin
From: Justin Kwan <jkwan@cloudflare.com> Sent: July 15, 2022 6:13 PM To: vignesh ravichandran <admin@viggy28.dev> Cc: pgsql-hackers <pgsql-hackers@postgresql.org>; vignesh <vignesh@cloudflare.com>; justinpkwan@outlook.com <justinpkwan@outlook.com> Subject: Re: Making pg_rewind faster
Looping in my other email.
On Thu, Jun 30, 2022 at 6:22 AM vignesh ravichandran <admin@viggy28.dev> wrote:
Hi Hackers,
I have been using pg_rewind in production for 2 years. One of the things that I noticed in pg_rewind is if it doesn't know what to do with a file "it copies". I understand it's the more safer option. After all, the alternative, pg_basebackup copies all the files from source to target.
However, this is making pg_rewind inefficient when we have a high number of WAL files. Majority of the data (in most of my cases 95%+) that it copies are WAL files which are anyway same between the source and target. Skipping those same WAL files from copying will improve the speed of pg_rewind a lot.
1. Does pg_rewind need to copy WAL files before the WAL that contains the last common check point?