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Re: redo copy latch

From: <daud11_at_hotmail.com>
Date: Fri, 13 Nov 1998 00:40:37 GMT
Message-ID: <72fv66$thc$1@nnrp1.dejanews.com>


Anjo Kolk

Do you think you can use the figures below to explain a little bit more, please?

NAME, GETS, MISSES, SLEEPS
redo copy, 1187, 1142 , 1445

EVENT, TOTAL_WAITS, TOTAL_TIMEOUTS, TIME_WAITED latch free, 158916, 78842 , 0

regards
Daud11

In article <364B4210.1958497_at_us.oracle.com>,   Kristiaan Johan Kolk <akolk_at_us.oracle.com> wrote:
> My guess is that this potential performance problem is very small compared to
> other issues that you may face:
>
> step 1:
> - look for 'latch free' in v$system_event, how much of the time_waited is really
> part of the overall wait time
>
> step 2:
> - look at v$latch to find the redo copy latch and the number of sleeps there
> are. (compare this to waits for latch free in v$system_event)
>
> step 3:
> - now you can determine how important these latch misses are for the
> performance.
>
> Anjo Kolk
> (I work for Oracle but I speak for my self).
>
> daud11_at_my-dejanews.com wrote:
>
> > Hi
> >
> > The ratio of MISSES to GETS for redo copy latch is more than 90% for my
> > oracle database. Does that mean that there is a problem with contention for
> > the redo copy latch? Should I increase the parameter LOG_SIMULTANEOUS_COPIES
> > to twice the number of CPU? Currently LOG_SIMULTANEOUS_COPIES = no of CPU
> > (2).
> >
> > Some explanations from you guys out there will be appreciated.
> >
> > thanks
> > Daud11
> >
> > -----------== Posted via Deja News, The Discussion Network ==----------
> > http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
>
>

-----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own Received on Thu Nov 12 1998 - 18:40:37 CST

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