10일 20일 30일 1 1 2 dbms_pipe.receive_me 3 PG_SLEEP20 4 WAITFOR 5 SLEEP20 2 6 dbms_pipe.receive_messagea20 1 7 OR 1 1 1 2 dbms_pipe.receive_me 3 3 PG_SLEEP20 3 4 WAITFOR 1 5 SLEEP20 3 6 dbms_pipe.receive_messagea20 1 7 OR 3 1 1 2 dbms_pipe.receive_me 3 PG_SLEEP20 2 4 WAITFOR 1 5 SLEEP20 3 6 OR 2 7 dbms_pipe.receive_messagea20 1 11위 - 20위