Re: add checkpoint stats of snapshot and mapping files of pg_logical dir - Mailing list pgsql-hackers

From Michael Paquier
Subject Re: add checkpoint stats of snapshot and mapping files of pg_logical dir
Date
Msg-id Yi/0KilcGi885sfJ@paquier.xyz
Whole thread Raw
In response to Re: add checkpoint stats of snapshot and mapping files of pg_logical dir  (Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>)
Responses Re: add checkpoint stats of snapshot and mapping files of pg_logical dir
List pgsql-hackers
On Mon, Mar 14, 2022 at 03:54:19PM +0530, Bharath Rupireddy wrote:
> At times, the snapshot or mapping files can be large in number and one
> some platforms it takes time for checkpoint to process all of them.
> Having the stats about them in server logs can help us better analyze
> why checkpoint took a long time and provide a better RCA.

Do you have any numbers to share regarding that?  Seeing information
about 1k WAL segments being recycled and/or removed by a checkpoint
where the operation takes dozens of seconds to complete because we can
talk about hundred of gigs worth of files moved around.  If we are
talking about 100~200 files up to 10~20kB each for snapshot and
mapping files, the information has less value, worth only a portion of
one WAL segment.
--
Michael

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