Re: Allowing multiple concurrent base backups
David Fetter <david@fetter.org>
From: David Fetter <david@fetter.org>
To: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Cc: marcin mank <marcin.mank@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Magnus Hagander <magnus@hagander.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2011-01-12T15:21:08Z
Lists: pgsql-hackers
On Wed, Jan 12, 2011 at 05:17:38PM +0200, Heikki Linnakangas wrote: > On 12.01.2011 17:15, David Fetter wrote: > >On Wed, Jan 12, 2011 at 10:26:05AM +0100, marcin mank wrote: > >>Considering that parallell base backups would be io-bound (or > >>network-bound), there is little need to actually run them in parallell > > > >That's not actually true. Backups at the moment are CPU-bound, and > >running them in parallel is one way to make them closer to I/O-bound, > >which is what they *should* be. > > That's a different kind of "parallel". We're talking about taking > multiple backups in parallel, each using one process, and you're > talking about taking one backup using multiple parallel processes or > threads. Good point. The idea that IO/network bandwidth is always saturated by one backup just isn't true, though. Take the case of multiple independent NICs, e.g. Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate