Re: Performance

From: Sybrand Bakker <postbus_at_sybrandb.demon.nl>
Date: Sat, 16 Sep 2006 02:19:13 +0200
Message-ID: <pggmg29n2g49ai8j7b92o3bubl38r7onv7@4ax.com>

On Fri, 15 Sep 2006 22:47:10 GMT, "Jack" <Jack_at_none.com> wrote:

>That i/o feels a bit sticky, maybe it is Solaris problem?
>Hopefully there is some manageable fix, i do not have contact with SA.
>And these kind of things cannot be done without hard evidence.

Hard evidence can be obtained by running truss -p on the dbw<n> process.
You'll see every lpwrite (IIRC) fail, and it will be followed by an ordinary pwrite.

And, IIRC, Solaris 5.8 doesn't have asynchronous I/O on default ufs file systems.
You may also need to look in mounting the filesystems with forcedirectio. This will bypass the Solaris filesystem cache. Note: the pagefile is IN the filesystem cache. There are several whitepapers on this topic, obtainable from Sun, or Sunsolve.

--
Sybrand Bakker, Senior Oracle DBA

Received on Fri Sep 15 2006 - 19:19:13 CDT