In one respect, there is provided a distributed database system that includes a global scheduler node and a first local scheduler node. The global scheduler node can be configured to generate an execution plan for a query requiring data stored at and/or managed by a first and a second worker node assigned to the first local scheduler node. The execution plan can include a first fragment having operations to be performed by the first and second worker node. The first local scheduler node can be configured to coordinate the execution of a portion of the first fragment of the execution plan by distributing, to the first and second worker node, operations included in the first fragment of the execution plan, and routing, between the first and second worker node, messages associated with executing the first fragment of the execution plan. Related methods and computer program products are also provided.