Re: Bug in slot.c and are replication slots ever used at Window?

From: Michael Paquier <michael(at)paquier(dot)xyz>
To: Konstantin Knizhnik <k(dot)knizhnik(at)postgrespro(dot)ru>
Cc: PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Bug in slot.c and are replication slots ever used at Window?
Date: 2018-08-31 18:46:47
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Hi Konstantin,

On Thu, Aug 30, 2018 at 11:27:31AM -0700, Michael Paquier wrote:
> It seems to me that you are right here, "path" points to
> pg_replslot/$SLOTNAME/state which is a file so the fsync is incorrect.
> I am not sure that we'd want to publish fsync_parent_path out of fd.c
> though, so perhaps we could just save the slot path in a different
> variable and use it?

I have spent more time on this bug, and the code path you have pointed
at is the only one having such an issue. Attached is a patch to fix the
problem. It includes the sanity checks I have used to check all code
paths calling fsync_fname() for both the frontend and the backend code.

The checks will not be included in the final fix, still they look useful
so I am planning to start a new thread on the matter as perhaps other
folks have more and/or better ideas.

Attachment Content-Type Size
slotpath_sync.patch text/x-diff 2.4 KB

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