Change of Logging Status: Implications? -Reply

Richard I would have thought that the 4gl programs would not be bothered by a move to transaction logging as Informix treats each sql statement as a singleton transaction anyway, so it should make no difference. I am not to sure about the esql/c. It depends on how it is constructed. We have been running into problems here with Cobol programs reading records 'with lock'. Then re-writing them later. This works fine under a non-logged database, but a database with logging frees the log immediately after the read (since it is not inside a transaction) with the result that the cobol re-write is over to failure. We are having to explicitly code transactions to work around this. If your c programs have some equivalent expectation then you might run into problems like this. HTH -- -- Peter Tashkoff NZ Kiwifruit Project Consultant/DBA Marketing Board. Standard Disclaimers apply This posting may not be used by any commercial organisation to vilify another. >>> Richard Spitz <spitz@GANS2X.ana.med.uni-muenchen.de> 1/August/1996 09:20pm >>> Dear Informix Experts, I just discovered that a large and complex application is running against a database with no logging. Needless to say, the whole application is written without transactions, which has been causing numerous consistency problems in the database. The developer has been catching most of these problems by giving support to the users over the phone and manually cleaning up after crashes, but this is now getting out of hand. I had to convince her that using transactions is mandatory, but I'm worried about the implications of changing over the database to logging mode. It is a large application with thousands of lines of code and using lots of cursors. I know that there are several things you can only do inside a transaction when the database is defined with logging, but I'm not sure I know all of them. So I need info about the implications of changing a database to logging mode. What problems are to be expected in what parts of a program? I'll have to assist the developer throughout the migration process, without knowing too much about the program itself and the database involved. If I did know, I'd probably quit my job as DBA... These problems have grown historically without me having had much influence, so please refrain from comments like "you should have known better". I just have to save as much as possible. Database Engine is ONLINE 5.03, the application is written using ESQL/C 5.01 and 4GL 4.10. All of this is running in client/server mode with both client and server running on SNI RM400 machines under SINIX 5.42B. Answers like "RTFM" are welcome as long as the tell me which FM to R. Regards, Richard -- +----------------------------+-------------------------------------------+ | Dr. Richard Spitz | INTERNET: spitz@ana.med.uni-muenchen.de | | EDV-Gruppe Anaesthesie | Tel : +49-89-7095-3413 | | Klinikum Grosshadern | FAX : +49-89-7095-8886 | | 81366 Munich, Germany | | +----------------------------+-------------------------------------------+