Query to find the blocking session in time interval.
set lines 170
set pages 10000
col event format a40
col sample_time format a40
select to_char(sample_time,’DD-MON-YY HH24:MI:SS’),SESSION_ID,SESSION_SERIAL#,SQL_ID,BLOCKING_SESSION,BLOCKING_SESSION_SERIAL#,BLOCKING_SESSION_STATUS,EVENT from dba_hist_active_sess_history where to_char(sample_time,’DD-MON-YY HH12:MI:SS’) between ’22-DEC-17 00:05 AM’ and ’22-DEC-17 09:10 AM’ and event like ‘%enq:%’ and BLOCKING_SESSION is not null order by 1 ;