is a difficult point although it is important.
Katsuhiko Okano
okano katsuhiko _at_ oss ntt co jp
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TIP 6: explain analyze is your friend
Hi,All.
Since the cause was found and the provisional patch was made
and solved about the CSStorm problem in previous mails, it reports.
Subject: [HACKERS] poor performance with Context Switch Storm at TPC-W.
Date: Tue, 11 Jul 2006 20:09:24 +0900
From: Katsuhiko Okano [EMAIL PROTECTED
Katsuhiko Okano wrote:
Since the cause was found and the provisional patch was made
and solved about the CSStorm problem in previous mails, it reports.
(snip)
(A) The algorithm which replaces a buffer is bad.
A time stamp does not become new until swapout completes
the swapout page
/lab_activities/kernel_testing/osdl_database_test_suite/osdl_dbt-1/
Thank you for the information.
I'll try it.
Regards,
Katsuhiko Okano
okano katsuhiko _at_ oss ntt co jp
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TIP 5: don't forget to increase your free space map
Jim C. Nasby wrote:
If you haven't changed checkpoint timeout, this drop-off every 4-6
minutes indicates that you need to make the bgwriter more aggressive.
I'll say to a customer when proposing and explaining.
Thank you for the information.
Regards,
Katsuhiko Okano
okano katsuhiko
Tom Lane [EMAIL PROTECTED] wrote:
Katsuhiko Okano [EMAIL PROTECTED] writes:
It does not solve, even if it increases the number of NUM_SUBTRANS_BUFFERS.
The problem was only postponed.
Can you provide a reproducible test case for this?
Seven machines are required in order to perform
Katsuhiko Okano wrote:
By PostgreSQL8.2, NUM_SUBTRANS_BUFFERS was changed into 128
and recompile and measured again.
NOT occurrence of CSStorm. The value of WIPS was about 400.
measured again.
not occurrence when measured for 30 minutes.
but occurrence when measured for 3 hours, and 1 hour
Hi.
Alvaro Herrera wrote:
Katsuhiko Okano wrote:
I suspected conflict of BufMappingLock.
but, collected results are seen,
occurrence of CSStorm and the increase of BufMappingLock counts
seem not to correspond.
Instead, SubtransControlLock and SubTrans were increasing.
I do
.
it seems to generate the subtransaction for every transaction.
How much is a possibility that
the LWLock to a subtransaction cause CSStorm?
best regards.
Katsuhiko Okano
okano katsuhiko _at_ oss ntt co jp
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TIP 5: don't
is a value smaller than the case where H/T is ON.
I think that it is because the performance of CPU fell.)
Regards
Katsuhiko Okano
okano katsuhiko _at_ oss ntt co jp
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