On Thu, Jan 20, 2011 at 2:10 PM, Dimitri Fontaine <dimi...@2ndquadrant.fr> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> I think that the basic problem with wal_level is that to increase it >> you need to somehow ensure that all the backends have the new setting, >> and then checkpoint. Right now, the backends get the value through >> the GUC machinery, and so there's no particular bound on how long it >> could take for them to pick up the new value. I think if we could >> find some way of making sure that the backends got the new value in a >> reasonably timely fashion, we'd be pretty close to being able to do >> this. But it's hard to see how to do that. > > Well, you just said when to force the "reload" to take effect: at > checkpoint time. IIRC we already multiplex SIGUSR1, is that possible to > add that behavior here? And signal every backend at checkpoint time > when wal_level has changed?
Sending them a signal seems like a promising approach, but the trick is guaranteeing that they've actually acted on it before you start the checkpoint. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
