Re: performance impact of archivelog

From: Andrew Kerber <andrew.kerber_at_gmail.com>
Date: Mon, 17 Nov 2008 09:28:27 -0600
Message-ID: <ad3aa4c90811170728q1ae894e6p54bcc31aaa974d39@mail.gmail.com>


Keep in mind that the 'expensive' operation with regard to redo is the file open/close and the physical switch to the next log. So, the key to minimize performance impact is to set the size of the redo log large enough that you are not continually switching logs. Oracle recommends a log switch every 15 minutes to half hour. So, you can use very large archive logs to handle high change time periods, and the archive_lag_target setting to make sure you are switching often enough during low activity time periods.

On Mon, Nov 17, 2008 at 9:18 AM, Renato M <renatomelogomes_at_gmail.com> wrote:

> Hi, list.
>
> I'm with the same doubt...
> We have a Data Warehouse database in "no archivelog" mode with 180GB/day of
> redo generation.
>
> because of a new backup solution/ strategie, we need put it in "archivelog
> ON".
>
> Claudia,
> Have you any other information about it ?
>
> Thanks a lot!
>
> Renato Gomes
> Eds, an HP Company.
>
>
>
> On Mon, Nov 17, 2008 at 9:09 AM, Roberts, David (GSD - UK) <
> david.h.roberts_at_logica.com> wrote:
>
>> 1. Performance cost of running in archivelog mode.
>>
>> We take our database out of archive log mode for a yearly batch process.
>> Very roughly the dry run (which is run on a different but similarly
>> specked machine in archive log mode) takes about 20% longer.
>>
>> Obviously as the difference is going to be dependent on how much change
>> is going on, your mileage may vary.
>>
>>
>> David Roberts
>> www.logica.com
>>
>> Logica UK Limited
>> Registered in England and Wales (registered number 947968)
>> Registered office: Stephenson House, 75 Hampstead Road, London NW1 2PL,
>> United Kingdom
>>
>> -----Original Message-----
>> From: oracle-l-bounce_at_freelists.org
>> [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Claudia Zeiler
>> Sent: 15 November 2008 21:27
>> To: oracle-l_at_freelists.org
>> Subject: performance impact of archivelog
>>
>> Has anyone on the list seen a discussion of
>>
>> 1. performance cost of running in archivelog mode.
>> 2. overhead of using partitions
>> 3. time calculation to perform statistics
>> 4. time savings of using statistics
>>
>> I always see these things discussed in terms of "more" but never in
>> terms of "how much".
>>
>> Thanks for any information that you can point me to.
>>
>>
>> Claudia Zeiler
>>
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>

-- 
Andrew W. Kerber

'If at first you dont succeed, dont take up skydiving.'

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Received on Mon Nov 17 2008 - 09:28:27 CST

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