Re: Serious Flaws in 7.23's Optimizer - Not using indexes

On Thu, 7 Aug 1997, Dan Pohlman wrote: > Actually, you should check out the Informix SQL Syntax guide for the > correct way to run update statistics. This varies between 7.10.UC1, > 7.10.UD1, 7.11.UC1 and 7.2x. For 7.23 it should be on page 1-631. > > In looking at this the correct steps are: > > update statistics medium for table table_name distributions only;> (note information in regard to large tables) > update statistics high for columns which head indexes > (note there should be one SQL statement per head column) > ( also keep in mind that this can be done with ) > ( distributions only since the next step takes care ) > ( of nrows, etc.) > update statistics low for all columns in the index > ( note this is a very important step and if not done properly) > ( incorrect paths can be taken. ) There's a .4gl to create this SQL for you at http://www.inxutil.com/ and at http://www.ntiug.org/ (latter site under construction, but that script should be there). Take a look. Note that I'm currently redoing it in esql/c. -Richard