From: Achilleas Mantzios <achill@matrix.gatewaynet.com>
To: pgsql-admin@lists.postgresql.org
Subject: Re: PostgreSQL 10.5 : Strange pg_wal fill-up, solved with the shutdown checkpoint
Date: Wed, 7 Nov 2018 12:33:56 +0200
Message-ID: <93155f7d-21e3-7442-5d76-acdaf57f0dae@matrix.gatewaynet.com> (raw)
In-Reply-To: <23169.1541516303@sss.pgh.pa.us>
References: <0d25bb8c-9cc7-10bc-71ba-6a8a8c33ec49@matrix.gatewaynet.com>
<46D70340-2172-406A-A346-B2D4C6E947E4@crazybean.net>
<6031b670-52d1-b823-6b41-35d2fa1873c6@matrix.gatewaynet.com>
<23169.1541516303@sss.pgh.pa.us>
On 6/11/18 4:58 μ.μ., Tom Lane wrote:
> Achilleas Mantzios <achill@matrix.gatewaynet.com> writes:
>> Remember : postgresql checkpointer decided to remove 5000+ files before shutdown. If any conditions were keeping those files afloat should also hold at this point, right.
>> The question is why didn't Postgresql removed them earlier.
> WAL files get removed/recycled after completion of a checkpoint. So
> apparently, checkpoints were not finishing during normal operation,
> but the shutdown checkpoint managed to terminate normally. That
> eliminates a lot of the usual theories about why checkpoints might
> not be succeeding (like a dirty buffer that always fails to be
> written, say as a result of broken permissions on its file).
>
> The only theory that comes to mind is that the checkpointer process
> was stuck somehow, but just "soft" stuck, in a way that allowed the
> postmaster's time-to-shut-down-please signal to unstick it. No,
> I have no idea how that could happen exactly. If it happens again,
> it'd be really interesting to attach to the checkpointer with a
> debugger and collect a stack trace.
Thank you Tom. Should I also re-run configure --enable-debug && make clean install ? Initially PostgreSQL was built without --enable-debug, so currently it does not show source code line numbers in
gdb bt .
>
> regards, tom lane
>
--
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt
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To: pgsql-admin@postgresql.org
Cc: achill@matrix.gatewaynet.com, pgsql-admin@lists.postgresql.org
Subject: Re: PostgreSQL 10.5 : Strange pg_wal fill-up, solved with the shutdown checkpoint
In-Reply-To: <93155f7d-21e3-7442-5d76-acdaf57f0dae@matrix.gatewaynet.com>
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