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Home -> Community -> Mailing Lists -> Oracle-L -> RE: RE: sequential reads/scattered reads
Are you sure that these are the ones that are slowing
the system down ? Did you try to find out at what
time of the day the system is really slow and execute
your wait/event queries at that time ? Did you get
a slice of 10046 data when the application was actually
running slow ? You could be looking at waits which
are not really the problem.
FWIW ! Mike
-----Original Message-----
Sent: Thursday, July 11, 2002 8:26 AM
To: Multiple recipients of list ORACLE-L
Cary Millsap,
i selected the top 25 SQL statements in the system over various periods . all are SELECT statements only waiting for reads.
querying v$session_wait also shows more than 10 records each for DB FILE SCATTERED READS and DB FILE SEQUENTIAL READS.does not it mean that it's b'coz of I/O contention ? i am not sure .
this is on RAID set up.
will not seperating my tables and indexes to seperate tablespace
help me ?
guide me Cary.it's really urgent.
i am novice DBA.
On Thu, 11 Jul 2002 Cary Millsap wrote :
>Moving stuff around won't reduce I/O traffic, it'll just spread
>it
>around across different devices.
>
>Don't focus on how much I/O your system does, focus on how much
>*time*
>an important process spends *doing* I/O. It's Amdahl's Law: If
>you
>improve I/O latencies by 50%, but your program spends only 2% of
>its
>response time doing I/O, then your program's response time will
>improve
>by only 1%.
>
>
>Cary Millsap
>Hotsos Enterprises, Ltd.
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: oraora oraora INET: oraoraora_at_rediffmail.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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Johnson, Michael INET: Michael.Johnson_at_oln-afmc.af.mil 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 Thu Jul 11 2002 - 12:23:52 CDT
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