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Home -> Community -> Usenet -> c.d.o.server -> Re: Multiple DBWR
A copy of this was sent to shreterh_at_my-dejanews.com
(if that email address didn't require changing)
On Fri, 26 Jun 1998 04:50:43 GMT, you wrote:
>Thomas, could I ask you a question about DBWR>1? I'm working from Digital
>Unix with one CPU so maybe this doesn't apply: One day I asked about
>multiple writers and I think Support said that there was an OS parameter that
>--should not-- be asynch if my dbwr > 1 because it would create errors. Now
>I see that you're looking at an --internal parameter-- covering the same
>ground...which of these are "usable" with DBWR > 1 (OS asynch y/n; param
>asynch y/n)?
>
I see in the problem report database that on digital unix, having db writers >1 and async io enabled at the OS level can cause issues (namely dbwr hangs -- no data loss, but a hang)...
If you have async io it is preferred to using multiple dbwr's to simulate it. so if async io is on, then having more then 1 dbwr is only wasting resources. Only if you don't have async io should you want to have more then 1 dbwr.
>Would appreciate being straightened out! Thanks in advance...
>
>> >I am running on Oracle 7.3.2 on Solaris 2.5.1. Currently I have only one
>> >DBWR. I would like to enable more DBWR inorder to improve I/O performance.
>> >Has anyone tried enabling multiple DBWR. If yes how much has the I/O
>> >performance improve? Many thanks...
>> solaris supports async io to both cooked and raw filesystems. Just make sure
>> async io is enabled, eg:
>>
>> SVRMGR> connect internal
>> Connected.
>> SVRMGR> show parameter async
>> NAME TYPE VALUE
>> ----------------------------------- ------- ------------------------------
>> disk_asynch_io boolean TRUE
>>
>> If async io is on, having more then 1 dbwr is a waste as multiple dbwrs are only
>> used to mimick async io...
>>
>> Thomas Kyte
>
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Thomas Kyte
tkyte_at_us.oracle.com
Oracle Government
Herndon VA
http://govt.us.oracle.com/ -- downloadable utilities
Anti-Anti Spam Msg: if you want an answer emailed to you, you have to make it easy to get email to you. Any bounced email will be treated the same way i treat SPAM-- I delete it. Received on Fri Jun 26 1998 - 08:04:24 CDT
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