Re: tracing makes the sql run faster

From: <Prasada.Gunda_at_hartfordlife.com>
Date: Mon, 1 Nov 2004 23:37:28 -0500
Message-ID: <OF4AE03B92.E6288617-ON85256F40.00183054-85256F40.00191E9B@hartfordlife.com>

I think I found the problem. I mentioned in my previous email that the tracing is making sql run faster and couldn't figure out what was going on.

I found in the v$sql_plan that the sql uses nested loops semi join when it runs slower. When I turn on the trace, it is using nested loops join and makes the query run faster. It is really strange why trace does this. Has any one experienced this before?

Another thing is, we just bounced the database. When I do the tests again, it is not using nested loops semi join even though there is _no_ trace on. Looks like CBO is changing plan during the day when there is a peak activity. I am not sure why it changes the plan. I will monitor it tomorrow and posts the findings.

Thanks.

Best Regards,
Prasad
860 843 8377

                                                                                                                                         
                      Prasada.Gunda_at_hartf                                                                                                
                      ordlife.com                To:       oracle-l_at_freelists.org                                                        
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                      oracle-l-bounce_at_fre        Subject:  tracing makes the sql run faster                                              
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                      11/01/2004 02:00 PM                                                                                                
                      Please respond to                                                                                                  
                      Prasada.Gunda

Hello All,

We have an application which uses Oracle Forms 6i. One particular query takes very long time when it runs in the forms application. When I trace the user session to see what was going on, surprisingly query runs much faster and tkprof output looks fine. This query runs faster when I run it sqlplus even with out the trace on.

How else I can trace to see what is going on? Did any one experience this before? I am working with Oracle but wanted to check here as well. Environment : 9.2.0.5 and Sun Solaris.

Any thoughts or inputs are much appreciated.

Thanks.

Best Regards,
Prasad
860 843 8377

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http://www.freelists.org/webpage/oracle-l Received on Mon Nov 01 2004 - 22:33:06 CST