Re: update stats resolution

Manoj Shroff wrote: > > Hi All, > > Does anyone have any guide lines for the use of the > resolution clause in "update statistics" ? Hi All, data distribution is an additional overhead for the optimizer. Therefore you should try to avoid data distributions whereever possible. If you really know, that the optimizer is choosing the wrong query path, and if you know, that the reason for the wrong query path is a not even distributed index data, then you can invoke update statistics high, better medium. By reducing the RESOLUTION factor, you will reduce the amount of data stored in sysdistrib. But as a result from a low RESOLUTION factor it could happen, that the amount of overflow-data will increase. I agree with the words of an informix consultant. First try to find the correct query path with update statistics high and the default resolution factor. If your query is now optimized in the correct way, you should reduce the amount of data in sysdistrib by using update statistics medium. Then you have to find a value for CONFIDENCE and RESOLUTION, so that your query will still be optimized in the correct way, and the information in the sysdistrib table will be small enough. Bye Stefan stefan@weideneder.de