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Concurrency wait. How I can resolve. [message #295327]

Tue, 22 January 2008 02:30

Oraclist
Messages: 33
Registered: January 2008
Location: Dhaka, Bangladesh

Member

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

Michel Cadot
Messages: 68665
Registered: March 2007
Location: Nanterre, France, http://...

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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

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Re: Concurrency wait. How I can resolve. [message #295345 is a reply to message #295327]

Tue, 22 January 2008 03:10

Oraclist
Messages: 33
Registered: January 2008
Location: Dhaka, Bangladesh

Member

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.

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Re: Concurrency wait. How I can resolve. [message #295348 is a reply to message #295345]

Tue, 22 January 2008 03:14

Michel Cadot
Messages: 68665
Registered: March 2007
Location: Nanterre, France, http://...

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It depends on your application and query.
The principle is: reach less often the hot blocks.

Regards
Michel

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Re: Concurrency wait. How I can resolve. [message #295359 is a reply to message #295327]

Tue, 22 January 2008 03:37

Oraclist
Messages: 33
Registered: January 2008
Location: Dhaka, Bangladesh

Member

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.".

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Re: Concurrency wait. How I can resolve. [message #295377 is a reply to message #295359]

Tue, 22 January 2008 04:06

Michel Cadot
Messages: 68665
Registered: March 2007
Location: Nanterre, France, http://...

Senior Member
Account Moderator

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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