Re: Problem with long transactions

bpk@evolving.com (Brad Knotwell) writes: >We currently are having a problem with "aborting long transactions." When >this occurs our logical logs (we have 6 @ 500 pages/log) fill up and tbtape >(running continuously) is unable to back them up. This situation fills >turbo.log with countless "Logical logs are full. . .etc." >We are able to recover okay but it is annoying (at the least). We are >going to increase the number of logs to ten in the future. >QUESTIONS: > 1) Does anyone think increasing the number of logical logs will help? > 2) Does anyone have any reasons why aborting a long transaction > would fill up the logs? Consensus around here is that for some > reason Informix is unable to rollback the transaction quickly > enough and other concurrent transactions fill the logs. If this > is the case why doesn't the database eventually "catch up?" When a long transaction is aborted, the rollback process will produce logical log records of its own. Aborting a transaction will never instantly free a log, and the rollback will take some time. Increasing your logical logs is certainly one solution. You didn't specify what version of Online you have, but 5.0 has long transaction high watermarks variables LTXHWM and LTXEHWM that you may set to a certain percentage level for a rollback (I believe 4.1 also has these on a few platforms but the feature may be undocumented). If these tbconfig variables are set to 80 and 90 respectively, then the oldest transactions would begin to be rolled back when the logs were 80% full, and all database processing (except the current rollbacks) would be suspended until a log is freed at 90%. Keith. ---------------------------------------------------------------------------------------- |brownlow@informix.com Keith Brownlow - Contractor| |brownlow@wet.com "These are my views and not those of Informix Software"| ----------------------------------------------------------------------------------------