In an example embodiment, event stream processing is performed by first parsing an input query into a directed acyclic graph (DAG) including a plurality of operator nodes. Then a grouping of one or more of the operator nodes is created. One or more partitions are created, either by the user or automatically, in the DAG by forming one or more duplicates of the grouping. A splitter node is created in the DAG, the splitter node splits data from one or more event streams and distributes it among the grouping and the duplicates of the grouping. Then, the input query is resolved by processing data from one or more event streams using the DAG.