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Runstat require after recall database dataset

 
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guptae

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Joined: 14 Oct 2005
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Location: Bangalore,India

PostPosted: Sat Sep 01, 2007 12:57 pm    Post subject: Runstat require after recall database dataset
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Hi All,

Why we used to do runstats after recalling database dataset?
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dick scherrer

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Joined: 23 Nov 2006
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PostPosted: Sat Sep 01, 2007 2:10 pm    Post subject:
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Hi Ekta,

RUNSTATS updates catalog statistics used by the optimizer to determine the fastest path to your data. This provides the best information possible to the optimizer.

When there is any data modification to the user tables, the catalog statistics tables are not automatically modified. A RUNSTATS command has to be performed on tables and indexes so that columns in the catalog tables are updated with the latest information.

It is necessary to provide the optimizer with accurate statistics describing the tablespaces and indexes so that it can choose an efficient access path for processing the data.
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guptae

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Location: Bangalore,India

PostPosted: Sun Sep 02, 2007 11:53 am    Post subject:
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Hi Dick,

Thanks for the information but i just want to now after recalling database PDS there should not be any need to do runstat again but why we do it?


I agree that runstat is require to update stats so that optimizer can choose the correct access path.
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dick scherrer

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PostPosted: Sun Sep 02, 2007 10:38 pm    Post subject:
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Hi Ekta,

I believe that is just insurance that the stats will always match the data after a recall is done.
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