Re: Update Statistics - Questions

Only if you specify the DROP DISTRIBUTIONS clause. With no options UPDATE STATISTICS is a LOW which does not create any data distributions but only updates the syscolumns and sysindexes (sysindices) statistics columns. But if you include DROP DISTRIBUTIONS with a LOW it will remove any data distributions created by MEDIUM or HIGH. Art S. Kagel ----- Original Message ----- From: Silvana Meza <smeza@fheg.follett.com> At: 1/15 19:03 > > > If you execute at 4 a.m.- "update statistics medium for table a, b, c" and > then > at 5 a.m. you runs "update statistics (without specifying level or any > tables)" > > Question: Does the last update statistic undo changed made by the first? > > The "Performance Guide for Informix Dynamic Server 7.31" does not state > which system tables > are updated by using "update statistics (without specifying level or any > table)" are they the > systables, syscolumns and sysindexes tables?....but it does state that when > you run > "update statistics medium for table a,b,c" the sysdistrib table is updated. > Yet when I do a > an isql select on sysdistrib it returns no rows found? > > The shop that I'm at does the above and I am trying to understand how the > update statistics> works. I just got the dostats utility created by Art Kagel and I plan on > creating a script that will > execute the utility for my large tables and create a separate script to > update statistics low for small> tables. > > > IDS 7.31uc7 > SQL 7.31uc4 > RS6000/ AIX 4.3.3 > > Thanks, > Silvana