On Thu, Sep 30, 2004 at 07:02:32PM +1200, Guy Thornley wrote:
> Sorry about the belated reply, its been busy around here.
>
> > > Incidentally, postgres heap files suffer really, really bad fragmentation,
> > > which affects sequential scan operations (VACUUM, ANALYZE, REINDEX ...)
> > > quite dra
Sorry about the belated reply, its been busy around here.
> > Incidentally, postgres heap files suffer really, really bad fragmentation,
> > which affects sequential scan operations (VACUUM, ANALYZE, REINDEX ...)
> > quite drastically. We have in-house patches that somewhat alleiviate this,
> > bu
Mark Wong <[EMAIL PROTECTED]> writes:
> I talked to Jan a little about this during OSCon since Linux filesystems
> (ext2, ext3, etc) let you use O_DIRECT. He felt the only place where
> PostgreSQL may benefit from this now, without managing its own buffer first,
> would be with the log writer. I'
On Thu, Sep 23, 2004 at 10:57:41AM -0400, Tom Lane wrote:
> Bruce Momjian <[EMAIL PROTECTED]> writes:
> > TODO has:
> > * Consider use of open/fcntl(O_DIRECT) to minimize OS caching
> > Should the item be removed?
>
> I think it's fine ;-) ... it says "consider it", not "do it". The point
> i
On Mon, Sep 20, 2004 at 07:57:34PM +1200, Guy Thornley wrote:
[snip]
>
> Incidentally, postgres heap files suffer really, really bad fragmentation,
> which affects sequential scan operations (VACUUM, ANALYZE, REINDEX ...)
> quite drastically. We have in-house patches that somewhat alleiviate this,
Bruce Momjian <[EMAIL PROTECTED]> writes:
> TODO has:
> * Consider use of open/fcntl(O_DIRECT) to minimize OS caching
> Should the item be removed?
I think it's fine ;-) ... it says "consider it", not "do it". The point
is that we could do with more research in this area, even if O_DIRECT
p
TODO has:
* Consider use of open/fcntl(O_DIRECT) to minimize OS caching
Should the item be removed?
---
Neil Conway wrote:
> On Mon, 2004-09-20 at 17:57, Guy Thornley wrote:
> > According to the manpage, O_DIRECT i
On Mon, 2004-09-20 at 17:57, Guy Thornley wrote:
> According to the manpage, O_DIRECT implies O_SYNC:
>
> File I/O is done directly to/from user space buffers. The I/O is
> synchronous, i.e., at the completion of the read(2) or write(2)
> system call, data is guaranteed to
A recent comment on this (or perhaps another?) mailing list about Sun boxen
and the directio mount option has prompted me to read about O_DIRECT on the
open() manpage.
Has anybody tried this option? Ever taken any performance measurements?
I assume the way postgres manages its buffer memory (deali
