Update Statistics

%UNIPLEX %TO informix-list@rmy.emory.edu %FROM rridley %SYSTEM DHLNET %SUBJECT Update Statistics %VERIFY y %DATE 26/03/93 18:35 %REFERENCE 16917 I have a question regarding the necessity of running 'update statistics' regularly: According to the article in Spring 1987 TechNotes, 'Because table size affects optimization, you should systematically update the table information so that RDSQL has current information.' Does this mean that, if I have a table of, say, 1 000 000 rows, and each day 30 000 rows are purged and another 30 000 rows are added, there is no need to run update statistics as the table size is relatively constant? Or did this only apply to Turbo, and if so, what are the other points to consider with Online ? I ask this because it sometimes takes up to an hour to run this utility in the field (when running it once a week), during which the database is locked - I guess this would suggest that we should balance 'running it more often and locking for less time' against 'running it less often and locking for more time' ? Does any-one know why it has to lock the entire database? Thanks in advance, Richard Ridley %UEND