JET 3.0 Query Optimization, Get with the Plan

JET 3.0 Query Optimization, Get with the Plan

If you need to analyze the performance of a Jet 3.0 query by thequery execution plan, you may do so by adding this registry keyand running regedit:

 \HKEY_LOCAL_MACHINESOFTWARE\_        MicrosoftJet3.0EnginesDebug

For the new Debug key, add a name value of JETSHOWPLAN (all capitalletters) and a data value of ON. Jet will generate a file calledSHOWPLAN.OUT, which will display query execution plans associatedwith your application. Because these files can get to be big quickly,please remember to set the data value to OFF once you’re done.

Well-designed queries and databases will generate query executionplans that refer to steps of the query execution that utilizetable indices and/or Rushmore technology as much as possible.Poorly designed ones often exhibit query execution steps wheretable scanning (reading rows sequentially) occurs.


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