A transaction processing system comprising a transaction log, a log management policy, a profile and a log manager, and method for managing the transaction log are provided. The method comprises maintaining a transaction log of recoverable changes made by transaction processing tasks; storing a log management policy including at least one log threshold and a plurality of possible actions associated therewith; and generating a historical profile comprising a set of acceptable values for characteristics of the log resource usage of tasks. Such log resource usage characteristics may include time taken for a task to complete, CPU resource consumed, number of log records made, etc. From a comparison of the profile behaviour to the actual behaviour of a task which has been identified as holding up trimming of the log, the likelihood that the identified task has entered an invalid loop and represents a ‘bad’ transaction instance, rather than simply just taking a long time to complete, can be inferred. Thus the most appropriate action can be selected and taken.