On Sun, Jan 19, 2014 at 03:37:37AM +0200, Marti Raudsepp wrote: > On Wed, Jan 15, 2014 at 5:34 AM, Jim Nasby <j...@nasby.net> wrote: > > it's very common to create temporary file data that will never, ever, ever > > actually NEED to hit disk. Where I work being able to tell the kernel to > > avoid flushing those files unless the kernel thinks it's got better things > > to do with that memory would be EXTREMELY valuable > > Windows has the FILE_ATTRIBUTE_TEMPORARY flag for this purpose. > > ISTR that there was discussion about implementing something analogous > in Linux when ext4 got delayed allocation support, but I don't think > it got anywhere and I can't find the discussion now. I think the > proposed interface was to create and then unlink the file immediately, > which serves as a hint that the application doesn't care about > persistence.
You're thinking about O_TMPFILE, which is for making temp files that can't be seen in the filesystem namespace, not for preventing them from being written to disk. I don't really like the idea of overloading a namespace directive to have special writeback connotations. What we are getting into the realm of here is generic user controlled allocation and writeback policy... > Postgres is far from being the only application that wants this; many > people resort to tmpfs because of this: > https://lwn.net/Articles/499410/ Yes, we covered the possibility of using tmpfs much earlier in the thread, and came to the conclusion that temp files can be larger than memory so tmpfs isn't the solution here. :) Cheers, Dave. -- Dave Chinner da...@fromorbit.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers