Re: Solaris Asynchronous I/O & Oracle

From: Gregg L. Kasten <gkasten_at_us.oracle.com>
Date: Mon, 22 Aug 1994 00:19:28 -0800
Message-ID: <gkasten-220894001929_at_gkasten-ppp.us.oracle.com>

In article <1994Aug10.185405.13734_at_dcs.warwick.ac.uk>, Intesar.Ali_at_dcs.warwick.ac.uk (Intesar Ali) wrote:

>
> Hi,
>
> I am wondering if anyone can shed any light on the matter of Asynchronous
> I/O (or AIO) on Solaris 2.3 with Oracle 7.0.16.4.
>
> I have my datafiles partitioned on five different disks, which is not to
> be confused with raw devics (as this is not an option for me,
> unfortunately), and wonder if I can set the parameter async_write=true to
> perform asynchronous writes!!!. This enables asynchronous writes (would
> you believe), on a Solaris system, but the documentation says that this is
> only possible on raw devices, yet I have used this on the database with
> five disks, which are not raw devices, and the database still retrieves
> data when queried, does ORACLE bypass this parameter if not applicable.
> Is there something that I have missed ??!!

Inte,

I can't speak for the Solaris 2.3 version of Oracle7 that uses async i/o But on the UnixWare 1.1 version of Oracle7 which supports async i/o, the dbwriter automatically verifies whether a datafile resides on a raw device before it attempts to write to it asynchronously. This way, your datafiles can reside on a mixture of file-system files and raw devices. To generalize very broadly, the more raw devices you have and the greater your (raw device)/(file system) datafile ratio, the better your dbwriter performance.

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Gregg L. Kasten               Oracle Corporation, UNIX Products Division
gkasten_at_us.oracle.com         Intel UNIX SVR4 Product Line Development 

The opinions expressed herein are not necessarily those of my employer. Received on Mon Aug 22 1994 - 10:19:28 CEST