Data synchronization in a data analysis system

A computer implemented method comprises receiving at least one log record 130 describing a type of operation performed in a source database system 101. Based on the type of operation, an update strategy is selected from a set of pre-defined update strategies. The update strategy specifies a sequence of replication operations to be performed in order to apply changes described in the at least one log record to a target database system 103. The change described in the log record may then be applied using the chosen update strategy in order to synchronize data across multiple databases. If the update of the target database fails, an alternative update strategy may be used instead. The method may be useful in a system in which both older and newer versions of the incremental update software are available, and a choice must be made about which to use.