Re: Timed_statistics

Is 8.1.7.2 the version where switching on timed_statistics has the odd side effect of stopping shareable SQL from being shared in certain circumstances. The consequence of an extreme attack of that would be a flooded shared pool and death by library cache latch contention.

Try taking snapshots of v$latch in the five minutes before, and the five minutes after switching on timed_statistics - ditto
v$system_events (which will, of course,
only give you the count of waits in the
before snapshot).

--
Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

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Norman Dunbar wrote in message ...


>Evening all,

>

>I've got a 'friend' who has a database at 8172 on a SUN box.

>This database is having some preformance problems.

>Running Statspack snapshots every half hour is fine.

>Doing it with timed_statitics = true is absolutely screweing

(technical


>term) the database.

>Response times plummet, users complain etc etc.

>

>I've never had any problems with T_S before myself, and I'm a bit

>stumped as to why the severe effect with this database.

>We know that there is a (serios) disc I/O problem (top wait is for 90

>mins out of an 8 hour uptime on 'db file sequential read') but CPU is

>mainly idle (8 processors, 2GB RAM).

>Discs are RAW and I've got him checking if it is software mirroring

or


>not, and if so is DIRTY REGION LOGGING on, and if so, where are the

>logging files (Thanks for that one Jonathan - last year at the Belfry

!)


>

>Any pointers please - the info from T_S is much better than without

it,


>but it is almost impossible to turn it on for long.

>

>

>Cheers,

>Norman.

>

>-------------------------------------

>Norman Dunbar

>Database/Unix administrator

>Lynx Financial Systems Ltd.

>mailto:Norman.Dunbar_at_LFS.co.uk

>Tel: 0113 289 6265

>Fax: 0113 289 3146

>URL: http://www.Lynx-FS.com

>-------------------------------------

>