Re: Forcing WAL flush - Mailing list pgsql-performance

From Jeff Janes
Subject Re: Forcing WAL flush
Date
Msg-id CAMkU=1w7GBWQ8XPZ2WOqw3OvUVzK9xuHQF2PPLtVWnvTb6+DWw@mail.gmail.com
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In response to Forcing WAL flush  (james <james@mansionfamily.plus.com>)
List pgsql-performance
On Mon, Jan 7, 2013 at 1:49 PM, james <james@mansionfamily.plus.com> wrote:
> Is there a way to force a WAL flush so that async commits (from other
> connections) are flushed, short of actually updating a sacrificial row?
>
> Would be nice to do it without generating anything extra, even if it is
> something that causes IO in the checkpoint.
>
> Am I right to think that an empty transaction won't do it, and nor will a
> transaction that is just a NOTIFY?

This was discussed in "[HACKERS] Pg_upgrade speed for many tables".

It seemed like turning synchronous_commit back on and then creating an
temp table was the preferred method to force a flush.  Although I
wonder if that behavior might be optimized away at some point.

Cheers,

Jeff


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