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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Meaning of V$WAITSTAT statistics
Yes, you are right, but my pupils... they WANT TO KNOW THE MEANING...
>From: Greg Moore <sqlgreg_at_pacbell.net>
>Reply-To: ORACLE-L_at_fatcity.com
>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Subject: Re: Meaning of V$WAITSTAT statistics
>Date: Tue, 02 Oct 2001 14:13:38 -0800
>
> > The Oracle 8i Reference manual Appendix A
>
>While it describes the wait events, it doesn't tell you which ones you can
>safely ignore when using waits for tuning.
>
>Even if you know which ones to focus on, the descriptions are pretty
>inadequate. We are informed that a "db file sequential read" means the
>session is waiting "while a sequential read from the database is being
>performed." On the other hand, a "db file scattered read" is "similar to db
>file sequential read, except that a session is reading multiple data
>blocks."
>
>Worse, suppose one of these two waits is twice as significant in my
>database
>than the other. Does that mean I have a problem and should start using the
>wait interface methodologies to track down the SQL that's causing the wait
>event to be high? Or is it normal that in a well tuned database that the
>one will be higher than the other by a factor of two? Or in fact is it
>typical in a well tuned database that the one that appears to be the least
>significant should actually be much lower, so I should focus on that? Or
>is
>there really no such thing as a typical profile for a well tuned database,
>because various wait events might be high on your system and low on mine
>simply because of the way they're used, so no one really has any idea what
>to focus on at any given time?
>
>--
>Please see the official ORACLE-L FAQ: http://www.orafaq.com
>--
>Author: Greg Moore
> INET: sqlgreg_at_pacbell.net
>
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-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Alejandra Pazos Freire INET: alepazosfreire2_at_hotmail.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Tue Oct 02 2001 - 16:26:06 CDT
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