RE: buffer busy waits

Aaaand, for those of you still at Oracle 8i, the "OTHER_WAIT" column in 9i/10g has a space in 8i, so the correct SQL for *8i* databases is:

SELECT WH.KCBWHDES "MODULE",SW.WHY0 "CALLS",SW.WHY2 "WAITS", SW."OTHER WAIT" "CAUSED WAITS"
FROM x$kcbwh WH, x$kcbsw SW
WHERE WH.indx = SW.indx
AND SW."OTHER WAIT" > 0
ORDER BY SW."OTHER WAIT" Sorry KG - Couldn't resist :( [See my notes in the OWI book AR]

John

-----Original Message-----

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of K Gopalakrishnan
Sent: Friday, July 29, 2005 3:57 PM
To: Brandon.Allen_at_oneneck.com
Cc: oracle-l_at_freelists.org
Subject: Re: buffer busy waits

Allen:

You can findout what are the _exact_ system calls causing the buffer busy waits using the following SQL. This will give a fair idea about the operations causing the bbw and you can narrow down the cause/action from the result.

SELECT WH.KCBWHDES "MODULE",SW.WHY0 "CALLS",SW.WHY2 "WAITS", SW.OTHER_WAIT "CAUSED WAITS"
FROM x$kcbwh WH, x$kcbsw SW
WHERE WH.indx = SW.indx
AND SW.OTHER_WAIT > 0
ORDER BY SW.OTHER_WAIT; Basically by reducing the concurrency at block level, you can easily combat the BBWs.

--

Best Regards,
K Gopalakrishnan
Co-Author: Oracle Wait Interface, Oracle Press 2004 http://www.amazon.com/exec/obidos/tg/detail/-/007222729X/
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http://www.freelists.org/webpage/oracle-l Received on Mon Aug 01 2005 - 12:51:54 CDT