Jonathan Lewis, 20.11.2012 15:37: > | Hello, > | > | I am analyzing some performance problems of an Oracle 10.2.0.5.0 2-node RAC > system and one figure in the > |AWR report caught my attention: > | > | Rollback per transaction %: 98.15 > | > | What exactly does this figure indicate, and what factors contribute to this? > | > > > The first things to check are the stats: > rollback changes - undo records applied > user commits > user rollbacks > transaction rollbacks > > If the first figure is very small it doesn't really matter how many > rollbacks you are doing, they are "no work" rollbacks. It is a common > feature of web app servers to issue a (redundant) rollback after every > single statement sent to the database - you may be seeing the effects of > such a WAS. > > If transaction rollbacks is much larger than user rollbacks then there may > be an internal problem of some sort - e.g. a loader program is constantly > trying to insert duplicate keys which are rolled back by Oracle, raising an > error that should be trapped (but might be ignored) by the application. > Thanks for the quick respsonse It indeed seems to be that "no work rollback" type of thing: Total per Second per Trans rollback changes - undo records applied 6 0.00 0.00 transaction rollbacks 3 0.00 0.00 user rollbacks 23,511 6.52 0.98 I already requested to get the configuration of the connection pools to find out if e.g. a "validation query" or something like that is configured to be a ROLLBACK statement. So, seeing the low number of "rollback changes", I assume the bottomline is that I don't need to worry and concentrate on the other bottlenecks that we have already identified. Regards Thomas -- //www.freelists.org/webpage/oracle-l