On Tue, May 16, 2006 at 06:48:25PM -0400, Greg Stark wrote: > Martijn van Oosterhout <kleptog@svana.org> writes: > > > > It might be easier to switch to giving each tape it's own file... > > > > I don't think it would make much difference. OTOH, if this turns out to > > be a win, the tuplestore could have the same optimisation. > > Would giving each tape its own file make it easier to allow multiple temporary > sort areas and allow optimizing to avoid seeking when multiple spindles area > available?
Only if those spindles weren't all in a single RAID array and if we went through the trouble of creating all the machinery so you could tell PostgreSQL where all those spindles were mounted in the filesystem. And even after all that work, there's not much that says it would perform better than a simple RAID10. What *might* make sense would be to provide two locations for pgsql_tmp, because a lot of operations in there involve reading and writing at the same time: Read from heap while writing tapes to pgsql_tmp read from tapes while writing final version to pgsql_tmp There's probably some gain to be had by writing the final version to a tablespace other than the default one (which is where pgsql_tmp would be, I think). But recent changes in -HEAD mean that the second step is now only performed in certain cases. -- Jim C. Nasby, Sr. Engineering Consultant [EMAIL PROTECTED] Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461 ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly