Managing a log-full condition of a transaction log in a transaction processing system, where the transaction log has a plurality of log records each associated with a particular transaction. When a log-full condition is detected, the active transaction having the oldest log entry of all active transactions is identified and logging for all transactions except for the identified transaction is temporarily suspended. A dynamic transaction backout of the identified transaction is initiated, with the writing of a backout record for the identified transaction to the log being delayed. Confirmation that the backout has completed is awaited before trimming the log. Then the delayed backout record for the identified transaction is written to the log, and normal logging is resumed.