Re: The dreaded sequential scan

Kenneth Almquist (ka@socrates.hr.att.com) wrote: : Informix 7.10.UC1 has a tendency to perform sequential scans (which : are *SLOW*) even when an index is available. According to Informix, : the way to avoid this problem is to run UPDATE STATISTICS after major : changes are made to a table. My problem is that I'm working on a : project which is supposed to store 20 million records using Informix. Update statistics needs to be done when there are **major** changes in a table.When your table goes from 10,000 to 10 million rows, the update is probably in order. When it goes from 10 million to 15 million, I'd question the need, unless the data distribution changes significantly. You may want to look at http://www.ztools.com and take a look at the info on zstats. This program is supposed to generate an "intelligent" script that updates your stats only as needed. I've just gotten a beta of the program and haven't looked at it much, but if it is as good as the rest of their tools I've beta'ed, it should be a winner. Watch these ztools folks. They're going to be a **big** influence in the DBA tools market. What I've seen so far is most impressive. Joe -- --------------------------------------------------------------------------- Joe Lumbley(jlumbley@netcom.com) ---------------------------------------------------------------------------