Patents - 11775560

11,775,560 - Method and system for using before images of changes for continuously comparing two databases which are actively being kept synchronized

An automated method and system are provided for comparing a source database and a target database that are intended to be kept in synchronization with each other. An application processes transactions that are posted to the source database and replicated to the target database. Before images of changes made to the source database resulting from transactions posted to the source database are collected into a first change log and then replicated to the target database. Before images of changes made to the target database resulting from replication are collected into a second change log. Representations of the before images of changes in the first change log are compared with representations of the before images of changes in the second change log that correspond to the same respective changes that were made to the source database and replicated to the target database. Corrective action is performed when the comparison indicates that the representations of the before images of changes in the first change log do not match the representations of the before images of changes in the second change log.