Re: Upgrade Informix version 5 to version 9

My input below... Art S. Kagel wrote in message <35ED95DA.220C@bloomberg.net>... >Anthony Burkitt wrote: >> >> My company has an application (compiled ESQL/C) running against Online >> version 5. >> In recent discussions, my management have been told by Informix that >> there are no great problems porting from version 5 to version 9 (My >> management appears to have been sold on the saleability of >> Object-Oriented). >> I do not know if Informix said (or implied this), or whether my >> management is jumping to conclusions, but they are now under the >> impression that we would probably not need to re-compiled the >> application for such an upgrade. I find this a difficult concept to >> believe. >> >> Could anyone out there confirm or deny this? >> Some facts would be most useful at this point... > >WELLLLLLLLL.... You CAN run the 5.0 executables against a 7/8/9 server, >however, since the 5.0 app expects to own a copy of the engine, ie the >SQLEXEC process, and 7/8/9 engines are independent and the connectivity >code was moved into the ESQL/C libraries, the 5.0 app will need to run >the SQL Remote Module (sqlrm) as its SQLEXEC process. This is basically >a protocol converter that lets 5.xx apps talk to local 7/8/9 servers. >This works but is VERY slow. If the server and apps are not on the >same machine the apps can continue to use the sqlexec client side >program and access the 9.xx engine remotely with no performance >penalty. > >You can recompile the 5.xx source with no modifications with the 9.xx >ESQL/C it just will not take advantage of any 7/8/9 specific features. >The advantage of this is that while you are porting your source and >testing you can be running the 9.xx apps against the 5.xx server which >works well (the app just treats the server as if it were a remote >engine you just cannot use shared memory connections). This works so >well that the 9.xx compiled apps will outperform the 5.xx apps running >against the 5.xx server. Then once all apps have been recompiled and >torture tested in production against the 5.xx engine the upgrade to >9.xx will be painless, at least from the application point of view, >since the recompiled apps will have already been tested and verified. > >This is the upgrade method I use and recommend. > >Art S. Kagel I agree with Art but I wouldn't trivialize (sp?) this effort. If your superiors think that this happens over the weekend... tell them to think again. Art may or may not agree but a thorough testing should be performed on all applications...This may also be an excellent time to consider changing certain functionality you have put off for so long. Changing a major revision of the engine requires a complete testing of the application...as does any major re-writing of functionality... why perform the testing effort twice if you can combine the two. Just my opinion. Rob Vorbroker Phone: 513/583-9888 Vorbroker Consulting FAX: 513/583-9932 www.vorbroker.com robv@vorbroker.com