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Concurrency wait. How I can resolve. [message #295327] Tue, 22 January 2008 02:30 Go to next message
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In my database concurrency wait problem is going on. I ran AWR report and got ,

Top 5 Timed Events
-----------------------
Event	Waits	Time(s)	Avg Wait(ms)	% Total Call Time	Wait Class
latch: cache buffers chains	37,078	5,894	159	37.3	Concurrency


How I can resolve the problem or what changes should I make so that concurrency problem would not occur.

[Updated on: Tue, 22 January 2008 02:30]

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Re: Concurrency wait. How I can resolve. [message #295330 is a reply to message #295327] Tue, 22 January 2008 02:34 Go to previous messageGo to next message
Michel Cadot
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Database Performance Tuning Guide
Chapter 10 Instance Tuning Using Performance Views
Section 10.3 Wait Events Statistics
Subsection 10.3.10 latch events
Paragrah 10.3.10.3.5 cache buffers chains

Regards
Michel
Re: Concurrency wait. How I can resolve. [message #295345 is a reply to message #295327] Tue, 22 January 2008 03:10 Go to previous messageGo to next message
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Thank you Michel, I read your link. I identify the hot block as well as segment and also the query for which concurrency wait problem happens. What will be my next step tuning SQL or what?

Thank you.
Re: Concurrency wait. How I can resolve. [message #295348 is a reply to message #295345] Tue, 22 January 2008 03:14 Go to previous messageGo to next message
Michel Cadot
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It depends on your application and query.
The principle is: reach less often the hot blocks.

Regards
Michel
Re: Concurrency wait. How I can resolve. [message #295359 is a reply to message #295327] Tue, 22 January 2008 03:37 Go to previous messageGo to next message
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One more thing, how can we achieve the goal, I mean what are the steps we need to aware of to abide the principle "reach less often the hot blocks.".
Re: Concurrency wait. How I can resolve. [message #295377 is a reply to message #295359] Tue, 22 January 2008 04:06 Go to previous message
Michel Cadot
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Is this the query?
Is this the program?
Is this many concurrent users?
You have to find who access the blocks and why.

Regards
Michel
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