Re: Update Statistics

Posted in 2005

Art S. Kagel — Wed, 14 Dec 2005 16:19:15 -0500 — source: Usenet: comp.databases.informix

Colin Dawson wrote: > This is some output from dostats > > TABLE(MEDIUM)...SUCCESSFUL (34.174 Secs) > COL1(HIGH)...SUCCESSFUL (963.907 Secs) > COL2(HIGH)...SUCCESSFUL (1061.096 Secs) > COL3(HIGH)...SUCCESSFUL (1250.274 Secs) > COL2, COL3(LOW)...SUCCESSFUL (2331.204 Secs) > COL4(HIGH)...SUCCESSFUL (898.998 Secs) > > The table has has 110M rows in it, is a LOW really necessary considering a > HIGH has already been run? Short answer, as andrew points out, is yes. You need a LOW on the exact set of columns for each index to update the sysindexes/sysindices record, plus to improve performance, the HIGHs are run with DISTRIBUTIONS ONLY since we're doing the LOWS anyway. Yes, the MEDIUM on the whole table will update syscolumns but not the depth and min/max key fields in sysindexes. Art S. Kagel