An operator manager may be configured to determine a number of available cores and to assign the cores among a plurality of operators of a query, the operators including a running set of operators through which a plurality of query paths exist. The operator manager may include a status monitor configured to determine the number of available cores and to determine the running set of operators, a critical path selector configured to determine a critical path of the query from among the query paths and the running set of operators, and a workload manager configured to assign a first core of the available cores to a running operator of the running set and of the critical path, and to thereafter receive a new critical path from the critical path selector and to assign a second core of the available cores to the running operator of the new critical path.