Re: Turn Transactions on?

Darin Strait wrote: > > The situation: > I'm on a short-term job at a site where there is no Informix guru. I'm > an Oracle guy modifying lots of someone else's Informix 4GL code. I have . . . > The questions: > Why would I not want to turn on the transaction log? (I assume that this > option was not exercised for some good reason and isn't the result of > someone forgetting about it.) > > If I was going to turn on the transaction log, how would I go about > doing it? > > With Informix SE, if transactions are implemented on a per-database > level, how can I find out if each (or any) of the three databases have > transactions turned on, besides writing a program that starts some > simple-minded transaction? > > TIA > -darin! > -- > Darin Strait The question about why the transaction log was not already turned on is a good one. Most production databases that I've seen and worked on have used the transaction log. The only reasons I could come up with about why it was not turned on are 1) disk space considerations and 2) the nature of the database may not call for explicit transactions to be used. Of these two reasons, it is hard to come up with a well written application which should not use transactions. The space consideration has to do with the standard engine not purging the transaction log automatically. If the log is left unmonitored in a relatively active database environment, it can easily fill up available disk space (the largest I have seen thus far was approx 970 MGs!). To start transactions, all you have to do is to go into isql or dbaccess. When prompted for a database name, press <DEL> (or your local interrupt key) - both dbaccess and isql will then take you into the query language without a database being selected (you can also use the close database statement if the database is already selected). The SQL statement to turn on the transaction log in the standard engine is simply "start database <databasename> with log in "<full pathname of logfile>". The next time you come into the database, transactions are available. Be aware that you should check the size of the logfile frequently and reset it's size to zero bytes as appropriate (unix: cp /dev/null logfile). Anyway, good luck, Bill Bounds VP Echo Management Group billb@qadas.com