Re: Forcing WAL flush

From: Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
To: james(at)mansionfamily(dot)plus(dot)com
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Forcing WAL flush
Date: 2013-01-07 23:56:51
Message-ID: CAMkU=1w7GBWQ8XPZ2WOqw3OvUVzK9xuHQF2PPLtVWnvTb6+DWw@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

On Mon, Jan 7, 2013 at 1:49 PM, james <james(at)mansionfamily(dot)plus(dot)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

In response to

Browse pgsql-performance by date

  From Date Subject
Next Message Merlin Moncure 2013-01-08 00:13:26 Re: Simple join doesn't use index
Previous Message james 2013-01-07 22:05:38 Re: Forcing WAL flush