MapReduce implementations provide fault tolerance, where you can re execute only failed mappers or reducers. By default, a partitioned parallel join execution would have to be rerun completely in case of even one node failure. It is possible to modify a parallel partitioned join execution to add fault tolerance in a manner similar to MapReduce, so failure of a node does not require full re execution of the query, but only actions related to that node. Explain what needs to be done at the time of partitioning at the sending node and receiving node to do this