PX COORDINATOR is the row source that corresponds to Query Coordinator (QC). This operation controls and schedules the parallel plan appearing below it in the plan tree.
This operation always has exactly one child row source which is PX SEND.
A PX COORDINATOR operation corresponds to a DFO tree.
create table tq84_px_t (
id number,
val varchar2(10)
) parallel 4;
explain plan for
select * from tq84_px_t
where
val = 'xyz';
select * from table(dbms_xplan.display(format => 'basic'));
--
-- ------------------------------------------
-- | Id | Operation | Name |
-- ------------------------------------------
-- | 0 | SELECT STATEMENT | |
-- | 1 | PX COORDINATOR | |
-- | 2 | PX SEND QC (RANDOM)| :TQ10000 |
-- | 3 | PX BLOCK ITERATOR | |
-- | 4 | TABLE ACCESS FULL| TQ84_PX_T |
-- ------------------------------------------
drop table tq84_px_t;