Runstat require after recall database dataset

guptae · Posted: Sat Sep 01, 2007 12:57 pm

Hi All,

Why we used to do runstats after recalling database dataset?

dick scherrer · Posted: Sat Sep 01, 2007 2:10 pm

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.

guptae · Posted: Sun Sep 02, 2007 11:53 am

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.

dick scherrer · Posted: Sun Sep 02, 2007 10:38 pm

Hi Ekta,

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