Horton

Re: Add checkpoint and redo LSN to LogCheckpointEnd log message

Fujii Masao <masao.fujii@oss.nttdata.com>

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From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: Nathan Bossart <nathandbossart@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Stephen Frost <sfrost@snowman.net>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, "Bossart, Nathan" <bossartn@amazon.com>, Julien Rouhaud <rjuju123@gmail.com>, Michael Paquier <michael@paquier.xyz>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-02-01T03:40:41Z
Lists: pgsql-hackers 

On 2022/02/01 10:44, Nathan Bossart wrote:
> On Tue, Feb 01, 2022 at 12:23:10AM +0530, Bharath Rupireddy wrote:
>> On Tue, Feb 1, 2022 at 12:00 AM Nathan Bossart <nathandbossart@gmail.com> wrote:
>>> I think the pg_controldata change needs some extra spaces for alignment,
>>> but otherwise these patches seem reasonable to me.
>>
>> Thanks. My bad it was. Changed in v6.

-				(errmsg("restartpoint complete: wrote %d buffers (%.1f%%); "
+				(errmsg("restartpoint complete: lsn=%X/%X, redo lsn=%X/%X; "
+						"wrote %d buffers (%.1f%%); "
  						"%d WAL file(s) added, %d removed, %d recycled; "
  						"write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s; "
  						"sync files=%d, longest=%ld.%03d s, average=%ld.%03d s; "
  						"distance=%d kB, estimate=%d kB",
+						LSN_FORMAT_ARGS(ControlFile->checkPointCopy.redo),
+						LSN_FORMAT_ARGS(ControlFile->checkPoint),

The order of arguments for LSN seems wrong. LSN_FORMAT_ARGS(ControlFile->checkPoint) should be specified ahead of LSN_FORMAT_ARGS(ControlFile->checkPointCopy.redo)?

Could you tell me why the information for LSN is reported earlierly in the log message? Since ordinally users would be more interested in the information about I/O by checkpoint, the information for LSN should be placed later? Sorry if this was already discussed.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

Commits

  1. Add checkpoint and REDO LSN to log_checkpoints message.