DISTRIBUTED SCHEDULING IN A MULTIPLE DATA SERVER SYSTEM

The scheduling functionality for a distributed system having multiple data servers is spread across the data servers rather than being centralized at a single machine. The distribution of the scheduling across multiple servers enhances the scalability of the system and enhances the fault tolerance of the system. Viewer state records are employed that contain scheduling information for viewers. Scheduling occurs by circulating the viewer state records amongst the data servers that are to provide the requisite data. The data servers output data blocks in a predetermined sequence based on how the data blocks are striped across the data servers. Each viewer state record is forwarded to a first successor and second successors in the scheduling sequence. The task of adding a viewer to a schedule is also distributed to the data servers.