US Patent 7689863 Restartable database loads using parallel data streams

A method and computer program for reducing the restart time for a parallel application are disclosed. The parallel application includes a plurality of parallel operators. The method includes repeating the following: setting a time interval to a next checkpoint; waiting until the time interval expires; sending checkpoint requests to each of the plurality of parallel operators; and receiving and processing messages from one or more of the plurality of parallel operators. The method also includes receiving a checkpoint. request message on a control data stream, waiting to enter a state suitable for checkpointing, and sending a response message on the control data stream.