Greg Stark wrote: > I couldn't get async I/O to work on Linux. That is it "worked" but > performed the same as reading one block at a time. On solaris the > situation is reversed. > > In what way is fadvise a kludge?
I think he is saying AIO gives us more flexibility, but I am unsure we need it. --------------------------------------------------------------------------- > > greg > > On 24 Oct 2008, at 01:44 AM, Bruce Momjian <[EMAIL PROTECTED]> wrote: > > > Jonah H. Harris wrote: > >> On Thu, Oct 23, 2008 at 4:53 PM, Greg Smith <[EMAIL PROTECTED]> > >> wrote: > >>>> I think the current plan is to use posix_advise() to allow > >>>> parallel I/O, > >>>> rather than async I/O becuase posix_advise() will require fewer > >>>> code > >>>> changes. > >>> > >>> These are not necessarily mutually exclusive designs. fadvise > >>> works fine on > >>> Linux, but as far as I know only async I/O works on Solaris. > >>> Linux also has > >>> an async I/O library, and it's not clear to me yet whether that > >>> might work > >>> even better than the fadvise approach. > >> > >> fadvise is a kludge. While it will help, it still makes us > >> completely > >> reliant on the OS. For performance reasons, we should be > >> supporting a > >> multi-block read directly into shared buffers. IIRC, we currently > >> have support for rings in the buffer pool, which we could read > >> directly into. Though, an LRU-based buffer manager design would be > >> more optimal in this case. > > > > True, it is a kludge but if it gives us 95% of the benfit with 10% of > > the code, it is a win. > > > > -- > > Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us > > EnterpriseDB http://enterprisedb.com > > > > + If your life is a hard drive, Christ can be your backup. + > > > > -- > > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > > To make changes to your subscription: > > http://www.postgresql.org/mailpref/pgsql-hackers -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://enterprisedb.com + If your life is a hard drive, Christ can be your backup. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
