query optimization

jmn@pdx.csd.mot.com (Jim Nielsen) write : >Can anyone tell me where I might find some definitive information on >how to optimize wildcard searches. > >I have a table which contains 300,000 records and I need to look up >records based on 6 possible fields. Some of the fields can be wildcarded. >In my experimentation, I have found some interesting but inexplicable timing >patterns. My documentation is of no assistance. > >Any help would be appreciated. 1) To get a feel for the relative cost of a query for comparison purposes execute the query after executing the following sql statement: set explain on; This will give you a relative cost for the query; it will also give the indexes and search paths used. MAKE SURE YOU RUN update statistics; FIRST. The information from explain will be written to a file in the current directory. 2) I recommend the class given by informix - "Optimizing Informix Applications" Warren J. Saccente Bell Communications Research Piscataway, NJ