Re: directio performance question

From: Max <trestusler_at_hotmail.com>
Date: 6 Jul 2003 15:54:31 -0700
Message-ID: <5a4548ca.0307061454.8ea7291@posting.google.com>

Sybrand Bakker <gooiditweg_at_sybrandb.demon.nl> wrote in message news:<ikfggvofqif50ci4p5kggkbrqfo887dbom_at_4ax.com>...
> On 6 Jul 2003 04:56:53 -0700, trestusler_at_hotmail.com (Max) wrote:
>
> >WHy is an index creation taking more time with directio ?
>
> You are posting insufficient information.
> forcedirectio applies to ufs filesystems only.
Thanks for the reply.
Sorry, it is UFS. didnt mention this because ufs is the default.

> disk_async_io = true.

isnt this the default ? Anyway a show parameters shows this to be true.

> directio a truss will show you your lwp.kaio requests fail and Oracle
> is reverting to normal buffered io.

This seems to be what is happening. truss reports

kaio(AIOWAIT, 0xFFFFFFFFFFFFFFFF)               Err#22 EINVAL

Reading some more newsgroup postings and articles from Sun it seems kaio is currently only available on raw and QIO with Veritas filesystems...

Guess I'll need to do a lot more reading but hopefully someone here can give a quick answer.

Is there any performance benefit to having a plain ufs filesystem mounted forcedirectio on solaris for oracle?

Max
>
>
> Sybrand Bakker, Senior Oracle DBA
>
> To reply remove -verwijderdit from my e-mail address
Received on Sun Jul 06 2003 - 17:54:31 CDT