Patent ID: 7756838

Claim:
A method for processing database transaction log files, the method comprising: invalidating a discard log file of a transaction log of a first database, wherein the discard log file is an unusable transaction log file comprising one or more log blocks of the transaction log having unusable data content that is to be discarded before the first database can begin processing new log records of database transactions received from a second database, wherein invalidating the discard log file comprises: (a) reading discard log information from a storage area, the discard log information comprising an indicator that the discard log file exists, a starting point identifier of the discard log file, and an ending point identifier of the discard log file, the discard log file comprising at least one log block of the transaction log having unusable data content that is to be discarded; (b) replacing the unusable data content of the at least one log block of the discard log file with an identifiably invalid data pattern that makes the log block content of the discard log file identifiable as invalid when scanning the transaction log, said identifiably invalid data pattern comprising a pattern of all zeros, a pattern of all ones or a pattern having a fixed combination of zeros and ones; and invalidating header information of the at least one log block; and (c) resetting the discard log information, the reset clearing the indicator that the discard log file exists; and overlaying identifiably invalid content of a discarded log block of the discard log file with new log records received from the second database, and using existing identifiably invalid content of the discard log file to detect an end of the transaction log, when scanning the transaction log during a recovery process from failure.