Method and system for avoiding blocking in a data processing system having a sort-merge network

In a system having producer and consumer processes, a producing process look ahead in its outgoing data stream to ensure that there is data available to consumers on all outgoing streams. The producer looks ahead by keeping a data array in its memory space with an entry for each connected consumer. When the outgoing data stream becomes blocked, the producer searches the array for empty connections. Then, the producer scans the outgoing data stream for messages to send over the empty connections and sends such messages. Periodically, the producer checks the original connection to see if the blocking condition has ended.