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Re: Very high CPU on OS side vs very high dbFileSeqRead on Oracle side...

From: Ed Stevens <nospam_at_noway.nohow>
Date: Fri, 05 Mar 2004 10:08:29 -0600
Message-ID: <n79h40hh9lhjk8j9ull2qqpb8sureg94dr@4ax.com>


On 5 Mar 2004 00:16:40 -0800, spendius_at_muchomail.com (Spendius) wrote:

>sybrandb_at_yahoo.com wrote...
>> [...]
>> This is an application/database design issue, what you are looking at
>> is the result of an ill-designed application which is constantly
>> querying/updating the same keys over and over again.
>That's what we've been beginning to suspect for a few days... But
>I guess you know the developers and project leaders: they can't
>stand the slightest form of critics.
>
>> 2 suggestions
>> Configure the keep and recycle buffer pools and put the affected
>> indexes in the keep buffer pool.
>Relevant.
>
>> Second suggestion: try using reverse key indexes.
>Not recommended: I know these constantly read/updated indexes
>are made on dates and that they're used with range scans (the app.
>displays tables with periods of time -selected by the user- on
>99% of its pages).
>
>> the size of the SGA is ...mmmm... ridiculous.
>No, it's sufficient. The server first had only 2 gigs of RAM,
>we upgraded to 4G not to increase the SGA, but to allow for
>sessions-related areas of memory (PGA/UGA) to grow as required
>(the server used to swap so hugely that the server crashed several
>times).
>Don't forget we have all the time between 130 to 170 sessions
>that easily eat up to 1G and more of memory. I checked it
>with
>#select se.sid,
># max(se.value) maxmem
>#from v$sesstat se,
># v$statname n
>#where n.statistic# = se.statistic#
>#and n.name in ('session pga memory', 'session uga memory')
>#group by se.sid
>#order by 2
>with a COMPUTE SUM OF MAXMEM ON REPORT.
>
>> Seems like a case of silver bullet tuning and more is better.
>Sorry here but my English is not good enough: what does "silver
>bullet" mean ?
>
>Thanks.

The 'silver bullet' is actually a reference to an old American movie and television western character called "The Lone Ranger". The Lone Ranger loaded his six-shooter with silver bullets and never missed his target. The term 'silver bullet' has fallen into the general vernacular as meaning a single, simple act that solves a complex problem with little or no effort. Received on Fri Mar 05 2004 - 10:08:29 CST

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