On Fri, Jan 7, 2011 at 01:47, Cédric Villemain <cedric.villemain.deb...@gmail.com> wrote: > 2011/1/5 Magnus Hagander <mag...@hagander.net>: >> On Wed, Jan 5, 2011 at 22:58, Dimitri Fontaine <dimi...@2ndquadrant.fr> >> wrote: >>> Magnus Hagander <mag...@hagander.net> writes: >>>> * Stefan mentiond it might be useful to put some >>>> posix_fadvise(POSIX_FADV_DONTNEED) >>>> in the process that streams all the files out. Seems useful, as long as >>>> that >>>> doesn't kick them out of the cache *completely*, for other backends as >>>> well. >>>> Do we know if that is the case? >>> >>> Maybe have a look at pgfincore to only tag DONTNEED for blocks that are >>> not already in SHM? >> >> I think that's way more complex than we want to go here. >> > > DONTNEED will remove the block from OS buffer everytime.
Then we definitely don't want to use it - because some other backend might well want the file. Better leave it up to the standard logic in the kernel. > It should not be that hard to implement a snapshot(it needs mincore()) > and to restore previous state. I don't know how basebackup is > performed exactly...so perhaps I am wrong. Uh, it just reads the files out of the filesystem. Just like you'd to today, except it's now integrated and streams the data across a regular libpq connection. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
