The sequence of operations that describes how a query will be broken down and executed by the SQLstream s-Server. The actual data flow is called a stream graph, which is a chain of stream nodes, each of which is a small software machine that applies some relational operation to its input data stream(s) to produce is output data stream(s). Named streams, or nexus nodes are defined by a CREATE STREAM statement. They are freestanding nodes to which other stream graphs can connect and disconnect, in order to receive or deliver data.
For more information see Background Concepts: Stream-graphs, Nodes, and s-Server in the Administration Guide.