Re: Fighting Words? Shared Pool Size

Glad i didn't have to cross light sabers with you, Obi Wan. <g>

The only icing i could add to this is to develop a nightly, dynamic pin script
based on loads, footprint, etc. from x$ksmlru ( ?think i got that right?) and
row cache, shared pool, and library cache latch activity. I'd love to learn more about the latch parent/child behavior, but don't know quite where to dip the stick in the river....also liked Andrew Babb's comments about (what i'll dub) namespace thrashing and i will be taking a look at that.

thanks all.

Steve Adams wrote in message <7fhvdv$ioh$1_at_nnrp1.dejanews.com>...
>Hi Guys,
>
>I believe that Ross is on the right track here. I've fought this battle
>several times. We have a 1400 connected (300 active) user system that only
>needs 50M of shared pool. Most shared pool latch contention comes down to
>long lists of chunks on the first and second free list buckets, and most
>library cache latch contention comes down to long collision chains hanging
>off the hash table. I'd go so far as to say, keep everything of value and
>flush the pool routinely.
>
>Regards,
>Steve Adams
>
>----------
>In article <7fh5ee$et3_at_dfw-ixnews12.ix.netcom.com>,
> "Ross Mohan" <postmaster_at_127.0.0.1> wrote:
>> >cursor_space_for_time will nearly always end up with a large shared
>> >pool.
>>
>> || I guess i was making the point that the pool was fixed, and too
large.
>> and that CSFT wasn't helping things by forcing additional pool mgmt
>>
>> As to what defines a large shared pool depends heavily on the
>> >number of applications that the instance has to support. After sizing
>> >exercises, I've ended up with Shared Pools ranging from about 20Mb's
>> >upto about 400Mb's. Both were about the correct size for the job they
>> >were being asked to perform.
>>
>> || Number of apps and users, plus considerations of pinning, reuse,
>> bindvars
>> versus not. I haven't ever seen the need ( up to, say, about 500
>> concurrent, busy
>> thin-client users, multiple apps ) to have a pool larger than 150MB.
On
>> your
>> machine with the 400MB pool, how many users did you have, and was it
>> something like an AR/AP or GL setup?
>>
>> >
>> >I think the important thing is that you don't see to much stealing of
>> >space from one object class (library cache, dictionary cache, sql area)
>> >to fund another. Keep an eye on the v$sgastat output over the course of
>> >time.
>>
>> || This is interesting. Have you experimented at all with monitoring
space
>> swapping between namespaces in the lib cache, and did you see
anything
>> there? Thinking about this will be useful, i believe....thanks for
>> the thoughts Andrew
>>
>>
>
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Received on Tue Apr 20 1999 - 01:32:06 CDT