Database poor performace

my database server giving poor performace(speed)
How can i find out which processes are eating more resources??
is there any SQL or Unix command..
PLz help.

> my database server giving poor performace(speed)
How can i find out which processes are eating more resources??
Poor performance can be caused by a wide and diverse range of factors - and resource consumption is only of the many of these.
Case in point. Some years ago a very large (Ingres/Corba) system was giving very poor performance. The guys had this huge plasma display showing the resource utilisation. CPU utilisation was less 25%. Memory utilisation was less than 50%. I/O utilisation was low. Network utilisation was low.
It was quite clear that resource utilisation was not the problem - but that all processes were queueing for a serialised resource. After pointing them in that direction, they discovered the problem. A page lock on a very heavily utilised table used for handing out sequence numbers. All the rows (carrying the latest sequences to be used per table) was lock for every single insert due to the Ingres page locking. So despite having some of the best (and most expensive) hardware, with the latest CPUs and tons of memory - all under utilised - the problem was a poor design choice and implementation.
Moral of the story - at times resource utilisation has nothing to do with performance, but application design and implementation always have everything to do with performance.
As for running a quick Unix or SQL command to diagnose the performance problem? That does not work. There are no Silver Bullets when it comes to performance. And I do not care about the qualifications or so-called (mis)experience of others that say otherwise.
Your first step should be to determine the cause of the performance problem. The "thing" that causes the "slow speed" of a process needs to be identified. Is the process waiting for I/O? Is it waiting for CPU time? Is it waiting for an exclusive table lock to be committed/rolled back? Etc. Etc.
Once you have identified the WHAT, then you can start at looking WHY it is happening and HOW to resolve it.
On the Oracle side, you would want to look at the various V$ views showing wait states, events, session statistics ito I/O, CPU, rows processed, etc. Run stats pack. Attempt to identify and isolate the WHAT in order to analyse it.

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>
The helper methods do database querries etc and return results that the EJB sends onwards to clients. If these methods
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>
No, if you dont have any static data variables in the Java classes, static method as such will not cause concurrency errors, and the methods should not be synchronized.
If you have any synchronized methods and they take a while to execute, that could become a bottleneck in itself, because different threads waiting for each other,
so make sure you dont have any synchronized methods where it is not explicitly needed.
Think of a static method (without static data in the class being manipulated) as a plain function in another programming-language.
>
We have some scaleability problems with the EJBs... It seems as if they do not run concurrently. If we do a stress test with several threads calling the EJBs their response time increases by a too large factor to feel comfortable...
>
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Edited by: JAeon on Sep 8, 2008 12:21 AM
Edited by: JAeon on Sep 8, 2008 12:22 AM

>
The helper methods do database querries etc and return results that the EJB sends onwards to clients. If these methods
are NOT synchronized (and the ejbs share the static class) won't it cause concurrency errors? I think most of our methods are not
synchronized (and it doesn't seem to cause any concurrency errors so far... though the system have not beeen stressed test that much,
and concurrency bugs tends to pop up later and randomly :P).
>
No, if you dont have any static data variables in the Java classes, static method as such will not cause concurrency errors, and the methods should not be synchronized.
If you have any synchronized methods and they take a while to execute, that could become a bottleneck in itself, because different threads waiting for each other,
so make sure you dont have any synchronized methods where it is not explicitly needed.
Think of a static method (without static data in the class being manipulated) as a plain function in another programming-language.
>
We have some scaleability problems with the EJBs... It seems as if they do not run concurrently. If we do a stress test with several threads calling the EJBs their response time increases by a too large factor to feel comfortable...
>
Apparently, you do have a some scaling/concurrency problem, which could have many causes -- transaction locking and clashes in the database, poorly configured database, network congestion, problems in the EJB architecture, etc -- can be many reasons...
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Hi,
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Thanks,
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To improve SQL query performance use Google for references:
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Hello
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Hello,
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Edited by: Lubiez Jean-Valentin on Nov 7, 2009 7:49 AM

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Hi all,
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