Did you try reducing _log_io_size to less than
one-third log_buffers size to make LGWR more active
and less busy .. We have had some success with it..
Thanks,
Ravi.
- Thomas Jeff <jeff.thomas_at_thomson.net> wrote:
> Jonathan,
>
>
>
> WILLING
> IMMEDIATE
> IMMEDIATE IMMEDIATE
> NAME GETS MISSES TO WAIT %
> GETS
> MISSES REQUEST % SLEEPS
> =============== =========== ========= ===========
> ===========
> =========== =========== =========
> redo copy 11448 0 0
> 599170378
> 405208 .0676281764 0
> redo allocation 6809468 247548 3.635350074
> 597056922
> 17812410 2.983368812 11018
>
> Thanks.
>
>
>
>
> -----Original Message-----
> Jonathan Lewis
> Sent: Friday, January 09, 2004 3:35 PM
> To: Multiple recipients of list ORACLE-L
>
>
>
>
> One interpretation of increased red latch contention
> and log buffer space waits is that more work is
> being
> done more quickly - so the log writer can't keep up.
>
> This could mean:
> a) the log writer has slowed down
>
> b) the database writer(s) have speeded up, so
> there
> is less time lost on write complete
> waits, free space
> waits, and (side effect) buffer busy
> waits.
>
> So the symptoms could be positive or negative, and
> we don't have enough relevant information to say
> which. Depending on the nature of the application,
> and the number and duration of sync waits, you could
> address the log buffer space waits by increasing the
> size of the log buffer.
>
> Are the redo latch waits allocation latch or copy
> latch ?
>
>
>
> Regards
>
> Jonathan Lewis
> http://www.jlcomp.demon.co.uk
>
> The educated person is not the person
> who can answer the questions, but the
> person who can question the answers -- T. Schick
> Jr
>
>
> Next public appearance2:
> March 2004 Hotsos Symposium - Keynote
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>
>
> One-day tutorials:
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>
>
> Three-day seminar:
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> ____UK___February
>
>
> The Co-operative Oracle Users' FAQ
> http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
>
> ----- Original Message -----
>
> Now, the Sr DBA here is screaming about the
> performance since I made the
> change, in particular, he says he's seeing high redo
> latch contention
> and redo log buffer waits which he says validates
> his contention that we
> need to get back to
> using DBWR_IO_SLAVES.
>
>
>
> --
> Please see the official ORACLE-L FAQ:
> http://www.orafaq.net
> --
> Author: Jonathan Lewis
> INET: jonathan_at_jlcomp.demon.co.uk
>
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Received on Fri Jan 09 2004 - 17:39:27 CST
