BroadcastExchangeExec

Insert by EnsureRequirements. This SparkPlan has to be child of BroadcastHashJoinExec or BroadcastNestedLoopJoinExec, which will call doExecuteBroadcast instead of doExecute on children. Thus doExecute will not be invoked and will throw Exception otherwise.

doExecuteBroadcast Produces the result of the query as a broadcast variable, and is invoked by BroadcastHashJoinExec.doExecute