URGENT:Q on Order of Update Stats

Hi all, I was following the informix recommendations (ver 7.2 ) for running UPDATE STATISTICS on our database, ie. MEDIUM, HIGH on columns heading an index, and LOW on all other columns of an index. This process is run once a week, and since it takes over 12hours, I tried to run multiple concurrent sessions of it. My question is this :- 1.Should the MEDIUM be run BEFORE the HIGH/LOW ? 2. Running the MEDIUM after the HIGH, removes all statistical information for the table from sysdistrib , ie it replaces the HIGH information with the MEDIUM. Does this affect anything ? Have I lost the whole purpose of doing a HIGH ?? This last weekend, I split the whole processess into 10 different sessions, put all the lows into one session, put some of the big tables ( HIGH ) into 9 different sessions, and the medium into another session. I waited for the low to finish before I ran the MEDIUM, but at the end of it all ( which took only an incredible 3 hours ), I do not see any information in SYSDISTRIB for a HIGH ( except for a few tables ). Also, my month-end processess took FOR EVER to finish this weekend. SO, have I messed up everything ? If I have, I need to correct it by the next two days. What is the order to be followed to run UPDATE STATISTICS ?? As always, I appreciate your response(s) Thanks Sujata ***************************************** Sujata Soman E-Mail: ssoman@omm.com O'Melveny & Myers, Los Angeles ******************************************