Re: Informix upgrade slows Delphi

In article <34F6FAD2.7123@bloomberg.com>, Art S. Kagel <kagel@bloomberg.com> writes >root@candle.pha.pa.us wrote: >> >> I had a client who just upgraded from Informix 7.1 to 7.2, and all of a >> sudden, all the queries are slow. Moving from field to field which does >> a single SQL table lookup takes 30-40 seconds. Seems like it is doing a >> sequential scan or something. >> >> Nothing has changed on the client end, including the Informix I-Net >> 5.10. He has many visual basic applications that also use the same >> I-Net on the same computer, and they work fine. >> >> Any ideas? How could a minor Informix upgrade cause this. > Check in your onconfig file that OPTCOMPIND is still set to 0. We went from 7.12 to 7.13 and OPTCOMPIND got changed from 0 to 2!! >Yes the optimizer got an intelligence injection in 7.2x so it may be >interpreting your table structure differently. If you have not done so >update statistics according to the instructions in the release notes>file SERVERS_7.2 (if those instructions are not there or are not >different from those in SERVERS_7.1 let me know I'll mail you the >updated recommendations or get my dostats.ec utility from my submission >to the IIUG software repository which implements these recs). If you >are doing multiple table joins you should also update statistics HIGH >on any join columns, in all joined tables, which are not already at >HIGH. > >In any event you should run the queries with SET EXPLAIN ON to >determine exactly what is happening. You may need to add indexes. > >If you still cannot improve things post a schema and representative >queries and someone will pitch in. > >Art S. Kagel -- David Williams Maintainer of the Informix FAQ Primary site (Beta Version) http://www.smooth1.demon.co.uk Official site http://www.iiug.org/techinfo/faq/faq_top.html I see you standin', Standin' on your own, It's such a lonely place for you, For you to be If you need a shoulder, Or if you need a friend, I'll be here standing, Until the bitter end... So don't chastise me Or think I, I mean you harm... All I ever wanted Was for you To know that I care