Patent ID: 7716181
Filing Date: 2010-05-11
Classification: G06F

Abstract:
1. A method of managing apply processing for data replication, to replicate changes made to a first data instance held at a source data processing system, the method comprising the step of: receiving a data transmission at a current data processing system, wherein the data transmission comprises a batch of descriptions of data changes made to the first data instance as a plurality of source transactions at the source data processing system; recording the transmitted data in intermediate persistent storage; at said current data processing system, separating the descriptions of data changes from the batch into sets of changes corresponding to their respective source transactions; and for each source transaction corresponding to the separated descriptions of data changes, applying the corresponding set of changes to a data replica at the current data processing system as a respective separate apply transaction, the applying step comprising writing a transaction processed record to indicate completion of the respective apply transaction; periodically checking the transaction processed records to identify data stored in said intermediate persistent storage corresponding to data transmissions for which apply transactions have been completed for all of the respective plurality of source transaction; checking whether deletion of said identified data would result in holes in the sequence of data transmission stored in the intermediate persistent storage; deleting a subset of said identified data, which subsets comprising the identified data that can be deleted without leaving holes in said sequence of data transactions; and deleting the transmitted data from said intermediate persistent storage in response to said check of the transaction processed records determining that apply transactions have been completed for all of the plurality of source transactions.