Re: Multi CPU Queries - Feedback and/or suggestions wanted!

Jonah H. Harris wrote:
> On Thu, Oct 23, 2008 at 4:53 PM, Greg Smith <gsmith@gregsmith.com> 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  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +