  1) First, we lock DWP_MERGE_E242F5DA52.target_events in TD_MAP1 for
     write on a reserved RowHash to prevent global deadlock.
  2) Next, we lock DWP_MERGE_E242F5DA52.target_events in TD_MAP1 for
     write.
  3) We do an all-AMPs STAT FUNCTION step in TD_MAP1 from
     DWP_MERGE_E242F5DA52.stage_events by way of an all-rows scan with
     no residual conditions into Spool 5 (Last Use), which is built
     locally on the AMPs in TD_MAP1.  The result rows are put into
     Spool 3 (all_amps), which is built locally on the AMPs.  The size
     is estimated with high confidence to be 275 rows (11,275 bytes).
     The estimated time for this step is 0.00 seconds.
  4) We do an all-AMPs RETRIEVE step in TD_MAP1 from Spool 3 (Last Use)
     by way of an all-rows scan with a condition of ("Field_4 = 1")
     into Spool 1 (used to materialize view, derived table, table
     function or table operator s) (all_amps), which is redistributed
     by the hash code of (DWP_MERGE_E242F5DA52.stage_events.event_id)
     to all AMPs in TD_MAP1.  Then we do a SORT to order Spool 1 by row
     hash.  The size of Spool 1 is estimated with low confidence to be
     207 rows (6,003 bytes).  The estimated time for this step is 0.00
     seconds.
  5) We do an all-AMPs merge with unmatched inserts into
     DWP_MERGE_E242F5DA52.target_events from Spool 1 (Last Use) with a
     condition of ("DWP_MERGE_E242F5DA52.target_events.event_id =
     EVENT_ID").  The number of rows merged is estimated with low
     confidence to be 207 rows.  The estimated time for this step is
     1.62 seconds.
  6) We spoil the parser's dictionary cache for the table.
  7) Finally, we send out an END TRANSACTION step to all AMPs involved
     in processing the request.
  -> No rows are returned to the user as the result of statement 1.