Oracle Hangs on Stored Proc Call or Commit

Problem

Error with Oracle hanging on a stored procedure call or commit statement.

Solution

Does someone have an uncommitted session? SQL Developer will sometimes cause this (maybe a user doesn’t have autocommit on?).

select
s.seconds_in_wait,
s.blocking_instance,
s.blocking_session,
s.event,
t.start_time,
s.sid,
s.serial#,
s.username,
s.status,
s.schemaname,
s.osuser,
s.process,
s.machine,
s.terminal,
s.program,
s.module,
to_char(s.logon_time,'DD/MON/YY HH24:MI:SS') logon_time
from
v$transaction t,
gv$session s
where
s.saddr = t.ses_addr
order by start_time;

Once you have a session id, use Sql Developer Tools > Monitor Sessions to see the problem SQL

See also this link on StackOverflow.