Re: Informix upgrade slows Delphi

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. 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 notesfile 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