Re: Having both dbwr_io_slaves and disk_asynch_io set

Richard,

DBWR_IO_SLAVES is a really poor attempt at asynch I/O, and it has dozens of bugs against it from v8.0.x through v9.2.0x. Don't take my word for it -- search MetaLink on the parameter name as keyword, be sure to click on "Advanced Search" and "Bug Database". It is a bottleneck to performance besides. Don't use it.

If you feel you need more bandwidth on your DBWR, then please consider setting DB_WRITER_PROCESSES > 1 -- setting it no higher than CPU_COUNT seems to work OK.

Hope this helps...

-Tim

on 12/6/04 8:21 PM, Richard Ji at richard.c.ji_at_gmail.com wrote:

> I found out on a database (8174, Solaris 8 Sparc, EMC) that I use,
> while disk_asynch_io is set to true, the dbwr_io_slaves is set to non zero, 6.
> And I am seeing a lot of "slave wait" events. The two obviously conflicts and
> I wonder what kind of effect this have caused when both are enabled.
>
> Thanks.
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> http://www.freelists.org/webpage/oracle-l
>

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