11,030,219 - Method for replacing a currently operating data replication engine with a new data replication engine without application downtime and while preserving target database consistency, and by using audit trail tokens
Abstract:An automated method is provided for replacing a currently operating data replication engine with a new data replication engine. The currently operating data replication engine replicates source database transactions including any new source database transactions committed in an audit trail of the source database before the currently operating data replication engine stops replicating. A list of active database transactions is generated and recorded as a first token in the audit trail. The currently operating data replication engine is stopped when all of the database transactions in the first token have completed. The new data replication engine is started and positioned to begin processing source database transactions in the audit trail of the source database at a beginning position that is located at or prior to the position of the first token in the audit trail. The new data replication engine replicates source database transactions by ignoring source database transactions listed in the first token and those which completed prior to the position where the currently operating data replication engine stopped, and replicates remaining source database transactions started prior to the current engine stopping, plus those new database transactions started after the currently operating data replication engine stopped.