Re: Optimiser choice of index

Colin Dawson wrote: > Update statistics high on 1st column in each index, low on other indexed> columns is what's recommneded by Informix, what else should I run? Recommended suite: HIGH on lead column of each index - DISTRIBUTIONS ONLY HIGH on first different key column if 2 or more indexes start with the same column(s) - DISTRIBUTIONS ONLY MEDIUM on all other columns - DISTRIBUTIONS ONLY (can be done in a single command) LOW for each full key list of every index Optimizations: For older servers (prior to 7.31xD3 and 9.30xC2) you can just start with a MEDIUM on the whole table. For newer servers you can gang all of the HIGHs into a single (or small number) of statements rather than doing individual columns (this is too slow on older servers). Or just run my dostats utility. Art S. Kagel > Regards > > Colin > > There are 10 types of people in the world, those that understand binary and > those that don't > > > > > > >>From: "scottishpoet" <dryburghj@yahoo.com> >>Reply-To: "scottishpoet" <dryburghj@yahoo.com> >>To: informix-list@iiug.org >>Subject: Re: Optimiser choice of index >>Date: 23 Sep 2005 03:45:06 -0700 >> >>1/ Bug in the optimiser >> >>2/ The Update Statistics strategy you used did not obtain appropriate >>information to provide the optimser with enough detail to choose the >>right index > > sending to informix-list