Re: HIGH latch free Wait on moving from RBO to CBO?
- From: Kirtikumar Deshpande <kedeshpande@xxxxxxxxx>
- To: VIVEK_SHARMA@xxxxxxxxxxx, oracle-l@xxxxxxxxxxxxx
- Date: Thu, 2 Mar 2006 14:06:29 -0800 (PST)
Hi Vivek,
There are a number of hidden parameters changed in 9i that affected CBO (as
compared to
8i CBO). I suggest contacting Oracle Support before changing any hidden
parameters. I
think this is know problem. If possible, test your application with 9.2.0.6.
That seems
to a stable version of 9i, so far.
Regards,
- Kirti
--- VIVEK_SHARMA <VIVEK_SHARMA@xxxxxxxxxxx> wrote:
>
> ISSUE - Getting HIGH Latch Free Wait on the following Latches after moving
> from RBO to
> CBO. ( ALL Objects been analyzed at 100 %). CPU Usage on DB Server has gone
> up by about
> 30 %. NOTE - Application has also been migrated to a Higher release along
> with the CBO
> movement.
>
> Qs Any init.ora parameters to Tune ?
>
> Would increasing _shared_pool_reserved_min_alloc to 6140 from the Default of
> 4400 Help?
>
> Setting cursorsharing = FORCE/SIMILAR caused "%sys" component of CPU Usage to
> shoot to
> 99 % within minutes of Database startup. Seemed to be hitting some Bug in
> 9.2.0.5 (64
> Bit) on Solaris 9. Has anybody experienced this & is it solved in a 9i Higher
> Patch ?
> Which Patch on 9i is advisable?
>
> Qs Will Tuning of individual SQLs reduce this wait ?
>
> Any Other Advice please?
>
> Top 5 Timed Events
> ~~~~~~~~~~~~~~~~~~ % Total
> Event Waits Time (s) Ela Time
> -------------------------------------------- ------------ ----------- --------
> latch free 17,386,965 457,377 63.67
> CPU time 121,612 16.93
> db file sequential read 142,824,481 72,252 10.06
> log file sync 982,290 28,909 4.02
> db file scattered read 8,532,496 14,464 2.01
> -------------------------------------------------------------
> Wait Events for DB: UBIFIN Instance: UBIFIN Snaps: 1515 -1517
>
> Latch Activity for DB:
> Pct Avg Wait
> Pct
> Get Get Slps Time NoWait
> NoWait
> Latch Requests Miss /Miss (s) Requests
> Miss
> ------------------------ -------------- ------ ------ ------ ------------
> ------
> cache buffers chains 4,141,035,268 0.3 1.2 0 311,630,019
> 26.7
> cache buffers lru chain 3,785,689 6.1 0.2 2300 321,104,446
> 25.1
> library cache 86,823,459 1.3 0.5 31780 56,524
> 17.4
>
>
> Database Size 1 TB , Number of Concurrent Users = 5000 ,
>
> Application Hybrid Application - Banking Product , Oracle 9.2.0.5 (64-Bit),
> Solaris 9,
> Number of CPUs on DB Server = 48
>
> Thanks Folks
>
> Vivek
>
> P.S. include my yahoo id (in CC) while replying please if possible
>
>
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