PL/SQL lock timer

A session simply sleeps for a pre-determined length of time specified in a call to the USER_LOCK.SLEEP or DBMS_LOCK.SLEEP procedures.

However it can appear that a session is locked or there is a performance issue.

The details of sessions with "PL/SQL lock timer" waits can be queried using the following SQL:

SELECT
   s.sid,
   s.seconds_in_wait,
   s.wait_class,
   s.event,
   s.p1text,
   s.p1,
   s.p1raw,
   s.serial#,
   s.program,
   s.client_identifier,
   s.terminal,
   s.command,
   ct.command_name,
   s.service_name,
   s.module,
   s.action,
   s.username,
   s.machine,
   s.sql_id,
   st.sql_text, -- just the first 64 characters of the SQL text
   st.hash_value
FROM v$session s,
     v$sqltext st,
     v$sqlcommand ct
WHERE st.sql_id (+) = s.sql_id
AND st.piece (+) = 0
AND ct.command_type (+) = s.command
AND s.event = 'PL/SQL lock timer'
ORDER BY s.seconds_in_wait DESC;

Reference:

Oracle E-Business Suite Performance Guide (Doc ID 1672174.1)