Horton

Re: Making pg_rewind faster

Japin Li <japinli@hotmail.com>

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From: Japin Li <japinli@hotmail.com>
To: John H <johnhyvr@gmail.com>
Cc: wenhui qiu <qiuwenhuifx@gmail.com>, Michael Paquier <michael@paquier.xyz>, Andres Freund <andres@anarazel.de>, Alexander Korotkov <aekorotkov@gmail.com>, Justin Kwan <justinpkwan@outlook.com>, Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers <pgsql-hackers@postgresql.org>, vignesh <vignesh@cloudflare.com>, vignesh ravichandran <admin@viggy28.dev>, "hlinnaka@iki.fi" <hlinnaka@iki.fi>, "jkwan@cloudflare.com" <jkwan@cloudflare.com>
Date: 2025-07-04T02:48:25Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. pg_rewind: Skip copy of WAL segments generated before point of divergence

  2. pg_rewind: Extend code detecting relation files to work with WAL files

  3. Split TESTDIR into TESTLOGDIR and TESTDATADIR

On Thu, 03 Jul 2025 at 12:59, John H <johnhyvr@gmail.com> wrote:
> Hi,
>
> On Wed, Jul 2, 2025 at 6:40 PM Japin Li <japinli@hotmail.com> wrote:
>>
>> >
>>
>> Splitting the logs from $PGDATA is definitely better. The question is whether
>> it's worth implementing this directly in core or if a prominent note in the
>> documentation would suffice.
>>
>
> I can work on the documentation update as a separate patch if folks
> think this is worthwhile.
>
>> >> On Wed, Jul 2, 2025 at 10:21 AM Japin Li <japinli@hotmail.com> wrote:
>>
>> Exactly!  It's confusing that getFileType() returns file_content_type_t
>> instead of file_type_t.
>>
>
> Ah yes that is confusing, updated in patch.
>
>> For v5 patch:
>>
>> 1.
>> We could simply use the global WalSegSz variable within decide_file_action(),
>> eliminating the need to pass wal_segsz_bytes as an argument.
>>
>
> Good point.
>
>> 2.
>> For last_common_segno, we could implement it similarly to WalSegSz, avoiding a
>> signature change for decide_file_actions() and decide_file_action().  I'm not
>> insisting on this approach, however.
>>
>
> I made it a global as well, and had to include access/xlog_internal.h
> in pg_rewind.h but I don't feel strongly about it either way.
>

Thanks, LGTM.

-- 
Regards,
Japin Li