Date: Tue, 3 Nov 2015 09:38:42 +0100
From: Andres Freund <andres@anarazel.de>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Vladimir Borodin <root@simply.name>, Oleksii Kliukin <alexk@hintbits.com>,
 Michael Paquier <michael.paquier@gmail.com>,
 pgsql-admin <pgsql-admin@postgresql.org>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: [ADMIN] Replication slots and isolation levels
Message-ID: <20151103083842.GQ11897@awork2.anarazel.de>
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On 2015-11-02 15:37:57 -0500, Robert Haas wrote:
> On Fri, Oct 30, 2015 at 9:49 AM, Vladimir Borodin <root@simply.name> wrote:
> > I’ve tried two ways - bare SELECT in autocommit mode and BEGIN; SELECT;
> > ROLLBACK. I first described the problem in thread on pgsql-admin@ [0], there
> > is copy-paste from psql there, but during conversation initial description
> > was lost.
> >
> > [0]
> > http://www.postgresql.org/message-id/7F74C5EA-6741-44FC-B6C6-E96F18D761FB@simply.name
> 
> Hmm.  That behavior seems unexpected to me, but I might be missing something.

The conflict is because of a relation lock, not because of
visibility. Hot-Standby feedback changes nothing about that.

I presume all the other conflicts are all because of relation level
locks? Check pg_stat_database_conflicts and the server logs to verify.

Andres


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