| From: | Neil Conway <neilc(at)samurai(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | ITAGAKI Takahiro <itagaki(dot)takahiro(at)lab(dot)ntt(dot)co(dot)jp>, pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: O_DIRECT for WAL writes |
| Date: | 2005-05-30 07:04:41 |
| Message-ID: | 1117436681.23266.41.camel@localhost.localdomain |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers pgsql-patches |
On Mon, 2005-05-30 at 02:52 -0400, Tom Lane wrote:
> Some googling suggests so, eg
> http://www.die.net/doc/linux/man/man2/open.2.html
Well, that claims that "data is guaranteed to have been transferred",
but transferred to *where* is the question :) Transferring data to the
disk's buffers and then not asking for the buffer to be flushed is not
sufficient, for example. IMHO the fact that InnoDB uses both O_DIRECT
and fsync() is more convincing. I'm still looking for a definitive
answer, though.
The other question is whether these semantics are identical among the
various O_DIRECT implementations (e.g. Linux, FreeBSD, AIX, IRIX, and
others).
-Neil
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Zeugswetter Andreas DAZ SD | 2005-05-30 08:01:56 | Re: compiling postgres with Visual Age compiler on OpenPower5 / Linux |
| Previous Message | Tom Lane | 2005-05-30 06:52:09 | Re: O_DIRECT for WAL writes |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Pavel Stehule | 2005-05-30 07:05:32 | SQLSTATE again |
| Previous Message | Tom Lane | 2005-05-30 06:52:09 | Re: O_DIRECT for WAL writes |