RE: CACHE/NOCACHE

Ravi,

The DB Buffer cache 'aging' algorithm has changed in 8.1.x - it is now based on a touch count algorithm. If the table is not updated and is frequently accessed, it will continue to remain in the Buffer cache, whether it is NOCACHE or not. Figuring out performance problems should usually start with looking at wait events, rather than the buffer cache. the 'Oracle Performance Tuning 101' book by Gaja Vaidyanatha and Kirti Deshpande of this list should be you first stop!

John Kanagaraj
Oracle Applications DBA
DBSoft Inc
(W): 408-970-7002

I don't know what the future holds for me, but I do know who holds my future!

• The opinions and statements above are entirely my own and not those of my employer or clients **

> -----Original Message-----
> From: Ravi Kulkarni [mailto:nandagokul_at_yahoo.com]
> Sent: Wednesday, July 02, 2003 4:41 PM
> To: Multiple recipients of list ORACLE-L
> Subject: CACHE/NOCACHE
>
>
> Gurus,
>
> Reposting.. since this might have got lost in emails.
> Any thoughts...?
>
> Thanks, -Ravi.
> "..
>
> Help me figure this one out. Was helping a colleague
> diagnose slow response time (8.1.7/Solaris running
> Peoplesoft ). x$bh showed 102,248 out of 170,000
> buffers belonged to a single table, which he said he
> cached explicitly. He did "NOCACHE" (on my suggestion)
> on the large table.
> I still find that the table is in buffer cache (even
> Buff# haven't changed - starts with buf#=1 - not sure
> if this means LRU end) even after a week. DB cannot be
> bounced since it is production.
> Do you know of any reason why it is not flushed out of
> cache when table is altered to NoCache?
>
> Thanks,
> Ravi.
>
> .."
>
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> Author: Ravi Kulkarni
> INET: nandagokul_at_yahoo.com
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-- 
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-- 
Author: John Kanagaraj
  INET: john.kanagaraj_at_hds.com

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