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