-- DISTRIBUTE_RESULT  |PARTITIONED|
  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
    -- STREAM_PROJECT  |PARTITIONED|
      -- SORT_MERGE_EXCHANGE [$$16(ASC) ]  |PARTITIONED|
        -- STABLE_SORT [$$16(ASC)]  |PARTITIONED|
          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
            -- STREAM_SELECT  |PARTITIONED|
              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                -- BTREE_SEARCH (test.DBLP.DBLP)  |PARTITIONED|
                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                    -- STABLE_SORT [$$20(ASC)]  |PARTITIONED|
                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                        -- LENGTH_PARTITIONED_INVERTED_INDEX_SEARCH (test.DBLP.ngram_index)  |PARTITIONED|
                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                            -- ASSIGN  |PARTITIONED|
                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|