The group_union node

This node is used to terminate and 'un-group' a grouped dataflow. It must be placed after a group_by node.

The group_union node acts as a union for grouped dataflows.

If this node is used without a group_by node, it will have no effect at all on the data-flow.

Note: The behaviour of using more than 1 group_union node within a flow is not defined.

See group_by


  %% 1 debug-node per group 
  %% end of grouping

An instance of the first debug node wil be started for every group, the second one will exist only once.