Hi,
We are maintaining unique session id in a table. once a session id pick as random we will be change the status as using mode until get response from third party service,then again simultaneously reusable.My scenario is parallely giving same session at a time even handle for update wait 2 as below

SELECT session_id  
        INTO v_session_id  
        FROM lf_session_log  
       WHERE (ROWID) IN (SELECT row_id  
                           FROM (SELECT ROWID row_id  
                                    FROM lf_session_log  
                                   WHERE query_state = 'R'  
                                         AND expdttime > sysdate  
                                         AND service_type = 1  
                                         AND session_type = 'P')  
                          WHERE rownum = 1)  
         FOR UPDATE wait 2;  
      
      UPDATE lf_session_log  
         SET query_state = 'U', expdttime = p_expdttime  
       WHERE session_id = v_session_id  
      RETURNING session_id INTO p_session_id;  
commit;  

Thanks,
Jai