Re: Remove wal_[sync|write][_time] from pg_stat_wal and track_wal_io_timing
От | Bertrand Drouvot |
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Тема | Re: Remove wal_[sync|write][_time] from pg_stat_wal and track_wal_io_timing |
Дата | |
Msg-id | Z7WjWf+Crs9NXY6b@ip-10-97-1-34.eu-west-3.compute.internal обсуждение исходный текст |
Ответы |
Re: Remove wal_[sync|write][_time] from pg_stat_wal and track_wal_io_timing
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Список | pgsql-hackers |
Hi, On Wed, Feb 19, 2025 at 01:32:33PM +0900, Michael Paquier wrote: > These additions feel unbalanced with the existing contents, and > overlap with the follow-up paragraph about the tuning that can be > guessed from the contents of pg_stat_io because the new content refers > twice to the section "WAL Configuration". Perhaps this could be > simpler, with one sentence in the tuning part? I would propose > something like: > For the WAL object, "fsyncs" and "sync_time" track the sync activity > of WAL files via issue_xlog_fsync(). "writes" and "write_time" track > the write activity of WAL files via XLogWrite(). See <xref > linkend="wal-configuration"/> for more information. > > My point is that the "WAL configuration" section already provides all > the details that were in pg_stat_wal removed in 0002 and added in > 0001, leading to duplicated contents. Makes sense, done that way in the attached. > > - 0002: Remove wal_[sync|write][_time] from pg_stat_wal, PendingWalStats and > > track_wal_io_timing. That does not make sense to split this work in sub-patches > > so that all of this in done in 0002. > > - 0003: remove the pgstat_prepare_io_time() parameter. Now that track_wal_io_timing > > is gone there is no need for pgstat_prepare_io_time() to get a parameter. > > 0002 and 0003 can be grouped in the same commit, IMO. Idea was to "ease" the review but I'm fine to merge them. Done that way in the attached. > - When <xref linkend="guc-track-wal-io-timing"/> is enabled, the total > + When <xref linkend="guc-track-io-timing"/> is enabled, the total > amounts of time <function>XLogWrite</function> writes and > <function>issue_xlog_fsync</function> syncs WAL data to disk are counted as > - <literal>wal_write_time</literal> and <literal>wal_sync_time</literal> in > - <xref linkend="pg-stat-wal-view"/>, respectively. > + <literal>write_time</literal> and <literal>sync_time</literal> in > + <xref linkend="pg-stat-io-view"/> for the wal <literal>object</literal>, respectively. > > Okay to update these are part of 0002 that removes the fields, but > there is also an argument about updating that on its own because this > is actually the case on HEAD? (No need to post an updated patch for > this remark.) That's right but that would mean almost duplicating the pg_stat_wal related stuff (because it can't be removed from the doc until the fields are gone). I think it's simpler to do it as proposed initially (the end result is the same). Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
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