Re: Performance problem

Timo H Jarvinen wrote: > > Hi, > > We have two almost identical ODS 7.23 databases on NT 4.0 Servers. The > schemas are exactly identical. However, when making a complex query, the > other one is 50% slower. The faster database has more data than the > slower one. No indexes are created on the databases, only primary keys > are used. > > The results of SET EXPLAIN: > Estimated Cost: 1224 (590) > Estimated # of Rows Returned: 549 (9) > > Any idea what may be the reason for the difference? Is the slower machine a copy of the faster machine? Maybe created by onunload/onload or something? You have not updated the statistics on that machine so the optimizer is doing a poor job. Update stats following the recommendations in the release notes ($INFORMIXDIR/release/en_us/0333/SERVERS_7.2) or get one of the excellent tools for doing this available on the IIUG Software Repository (as soon as the crash recovery is complete). One of these is my own dostats.ec (if you have ESQL/C) in the submission utils2_ak. BTW new versions of dostats.ec and myschema.ec are being uploaded today as an update to utils2_ak and should find their way into the Repository in a week or two. Art S. Kagel