OPTIMIZED EXECUTION OF QUERIES INVOLVING EARLY TERMINABLE DATABASE OPERATORS

摘要

According to embodiments, a multi-node database management system allows consumer processes (“consumers”) implementing a portion of a distributed data-combination operation to independently send a STOP notification to corresponding producer processes (“producers”). Upon a given consumer determining that the consumer requires no further information from corresponding producers, the consumer sends a STOP notification to the producers. When a given consumer sends out a STOP notification, the producers drop any data destined for the given consumer and also stops preparing data for and sending rows to the given consumer. Furthermore, once the producers receive STOP notifications from all of the consumers corresponding to the producers, the producers stop the current sub plan execution immediately without requiring completion of the sub plan. Thus, embodiments significantly improve the query execution performance by avoiding scanning and distributing data that is not needed for execution of the distributed operation.