Oninit cdi / Archive
Talk to an expert →

SQL-Explain when upgrading IDS

Posted in 1999

Topics: Installation, Setup & Upgrades, SQL Development & Query Writing, Migration, Import/Export & Data Conversion

Tony Flaherty — — source: Informix-list mailing list archive (1991-1998)

Hi, I'm preparing to upgrade OnLine from 7.24.UC5 to 7.30.UC7. The migration manual recommends generating the output from some SQL by setting explain on and then comparing the results before and after the upgrade to ensure the access paths have not changed. What do people normally do for this? I can do a series of queries with joins etc. on my main tables but doing the whole lot is infeasible. Is this step really necessary at all? -- --------------------------------------- Tony Flaherty aef@mfs.misys.co.uk Analyst Programmer Misys Financial Systems All statements and opinions are my own, Misys don't pay me enough to have opinions on their behalf .

↪ replying to Tony Flaherty
Yuri Dovgart — — source: Informix-list mailing list archive (1991-1998)

In article <929368622.13017.0.nnrp-07.c1ed1f69@news.demon.co.uk>, "Tony Flaherty" <aef@mfs.misys.co.uk> wrote: Hi Tony. Generally speaking, you need this step in OLTP systems for queries, that executes very often. This helps you to tune your optimizer statistics. This step is needed in this case : after upgrade all your queries seems to be slow. To understand, what is the reason, you can compare query plans before and after update. If they differ - this is the reason. In the other way the problem is not in the optimizer and it's statistics. Hope, this help -- With best regards, Yuri Dovgart, SAP R/3, Informix consultant, "Telecominvest" company. E-mail y_dovgart@tci.ukrtel.net > Hi, > I'm preparing to upgrade OnLine from 7.24.UC5 to 7.30.UC7. The > migration manual recommends generating the output from some SQL by setting > explain on and then comparing the results before and after the upgrade to > ensure the access paths have not changed. What do people normally do for > this? I can do a series of queries with joins etc. on my main tables but > doing the whole lot is infeasible. Is this step really necessary at all? > > -- > --------------------------------------- > Tony Flaherty aef@mfs.misys.co.uk > Analyst Programmer > Misys Financial Systems > All statements and opinions are my own, > Misys don't pay me enough to have opinions > on their behalf > > . > > Sent via Deja.com http://www.deja.com/ Share what you know. Learn what you don't.

Glossary