Re: performance question

  • From: Joan Hsieh <joan.hsieh@xxxxxxxxx>
  • To: Ron Crisco <ron.crisco@xxxxxxxxxxxx>
  • Date: Tue, 13 Apr 2010 12:07:14 -0400

Hi Ron,
I turned on 10053 trace, both ran out of memory, it generated huge trace file though, I have to split the file to open it. I will take a look. 

thanks,

Joan

Ron Crisco wrote:
Rather than guessing, you can know the answer. Just run 10053 tracing in both instances and compare. To interpret the results, I highly recommend a paper written by Wolfgang Breitling, available at http://www.centrexcc.com/A%20Look%20under%20the%20Hood%20of%20CBO%20-%20the%2010053%20Event.pdf 

Ron Crisco
On Tue, Apr 13, 2010 at 9:54 AM, Joan Hsieh <joan.hsieh@xxxxxxxxx <mailto:joan.hsieh@xxxxxxxxx>> wrote: 

    Hi dear listers,

    I have a very strange performance issue which I couldn't figure it out.
    I have 2 11.2.0.1 databases with the exactly same parameters, they
    both on the same server. One sql statement run on both database
    generated 2 diff plans. So I exported the whole schema stats from
    the good db, imported it to the bad one. It didn't change the
    result. I can easily fix the performance issue on the bad db by
    setting optimizer_feature_enabled to 10g, but I just wondering why
    the 2 databases have different plans even after I imported the stats
    and checked the stats.

    Thanks,

    Joan



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