On Wed, Sep 20, 2006 at 05:50:48PM -0400, Tom Lane wrote: > "Jim C. Nasby" <[EMAIL PROTECTED]> writes: > > My thought is that in many envoronments it would take much beefier > > hardware to support N postmasters running simultaneously than to cycle > > through them periodically bringing the backups up-to-date. > > How you figure that? The cycling approach will require more total I/O > due to extra page re-reads ... particularly if it's built on a patch > like this one that abandons work-in-progress at arbitrary points. > > A postmaster running WAL replay does not require all that much in the > way of CPU resources. It is going to need I/O comparable to the gross > I/O load of its master, but cycling isn't going to reduce that at all.
True, but running several dozen instances on a single machine will require a lot more memory (or, conversely, each individual database gets a lot less memory to use). Of course, this is all hand-waving right now... it'd be interesting to see which approach was actually better. -- Jim Nasby [EMAIL PROTECTED] EnterpriseDB http://enterprisedb.com 512.569.9461 (cell) ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings