Re: HIGH latch free Wait on moving from RBO to CBO?

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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