A system, method and computer-readable medium provide for assigning sampling methods to each input stream for arbitrary query sets in a data stream management system. The method embodiment comprises splitting all query nodes in a query directed acyclic graph (DAG) having multiple parent nodes into sets of independent nodes having a single parent, computing a grouping set for every node in each set of independent nodes, reconciling each parent node with each child node in each set of independent node, reconciling between multiple child nodes that share a parent node and generating a final grouping set for at least one node describing how to sample an input stream for that node.