From: Victor Sudakov <vas@sibptus.ru>
To: pgsql-admin@lists.postgresql.org
Subject: Re: index bloat estimation
Date: Wed, 17 Feb 2021 09:27:24 +0700
Message-ID: <YCx/DJkZRw0mzRyr@admin.sibptus.ru> (raw)
In-Reply-To: <CAODZiv5uVWASjuigUxJhmxmrQAdMoOxRu5vz97CkbuqH2-oxow@mail.gmail.com>
References: <YCY7oPIXobbY8oPu@admin.sibptus.ru>
<CAODZiv6YZj3GJsTv5_dp07VS2FACrFu_JPWsFVi64=1mJD_t0A@mail.gmail.com>
<YCn8BmEe/4mA0KIb@admin.sibptus.ru>
<CAODZiv5uVWASjuigUxJhmxmrQAdMoOxRu5vz97CkbuqH2-oxow@mail.gmail.com>
Keith Fiske wrote:
[dd]
>
> You cannot run the actual scan on the replica, no. But it can be set to run
> against the replica and just report the statistics so you can have a cron
> set up to always run on the given system in case of failover. The
> "--recovery_mode_norun" can be set so it will only run if the target system
> is actually a primary.
>
> I could possibly see about letting this actually run against the replica,
> however this can be a rather long running transaction depending on the size
> of the tables involved. You can set the "--commit_rate" to avoid some of
> that, but if you have really large tables, it can still run quite long. So
> this sort of check is really best run against the primary to avoid issues
> around having to allow long running queries on the replica (delayed
> replication or even worse bloat buildup).
If you have a dedicated replica for OLAP, even one running from a WAL
archive (not from a replication slot), this is not an issue.
So running pg_bloat_check against a replica would be very useful for
some of us.
--
Victor Sudakov, VAS4-RIPE, VAS47-RIPN
2:5005/49@fidonet http://vas.tomsk.ru/
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To: pgsql-admin@postgresql.org
Cc: vas@sibptus.ru, pgsql-admin@lists.postgresql.org
Subject: Re: index bloat estimation
In-Reply-To: <YCx/DJkZRw0mzRyr@admin.sibptus.ru>
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