Re: number of redolog groups

Howard J. Rogers wrote:

>"Daniel Morgan" <damorgan_at_x.washington.edu> wrote in message
>news:1068225157.763394_at_yasure...
>
>
>>Robert wrote:
>>
>>
>>
>>>Hi,
>>>
>>>Is there any reason to have more than two redolog groups in NOARCHIVE LOG
>>>mode?
>>>
>>>Thanks in advance.
>>>
>>>
>>>
>>>
>>>
>>Assuming based on the NOARCHIVE LOG mode that data recovery is not a
>>priority ... no.
>>
>>
>
>Sorry Daniel, that's not correct. In noarchivelog mode, there is still
>nevertheless a checkpoint issued at each log switch, and with only two log
>groups to hand, it is entirely possible to fill up the second log before the
>first one has been checkpointed successfully. And if that happens, your
>database will stall until DBWR and CKPT catch up.
>
>Having more online log groups will therefore buy these two processes the
>time needed to finish the checkpoint, for the log status to therefore change
>from 'ACTIVE' to 'INACTIVE' and therefore for the recycling of redo logs to
>proceed without a database stall now an then. So yes, there still is a use
>for more than two online log groups, even in noarchivelog.
>
>It's for that reason that I *always* suggest three logs should be considered
>the minimum practical number of online logs.
>
>Regards
>HJR
>
>

Log file groups or log file members? The question was about groups.

I see no point in having more than two groups. I see a lot of point in having more than two members to a group. Or am I having an attack of syntax dyslexia?

-- 
Daniel Morgan
http://www.outreach.washington.edu/ext/certificates/oad/oad_crs.asp
http://www.outreach.washington.edu/ext/certificates/aoa/aoa_crs.asp
damorgan_at_x.washington.edu
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