Current isolation level in oracle

Question

How to get the current (default) transaction isolation level in oracle?

Answer 1

Using the query from the SO answer Vincent Malgrat referenced, here is how you can get the transaction isolation level for the transaction in progress:

SELECT s.sid, s.serial#,
   CASE BITAND(t.flag, POWER(2, 28))
      WHEN 0 THEN 'READ COMMITTED'
      ELSE 'SERIALIZABLE'
   END AS isolation_level
FROM v$transaction t 
JOIN v$session s ON t.addr = s.taddr AND s.sid = sys_context('USERENV', 'SID');

If you are not already in a transaction you can start one with the following:

declare 
   trans_id Varchar2(100);
begin
   trans_id := dbms_transaction.local_transaction_id( TRUE );
end;
/

It seems like there would be an easier way than this. I don't know how to get the default isolation level for the session if that is what you are looking for.

Answer 2

-- I am using something like below

with q1 as ( select distinct name, isdefault, value ,decode(value,'serializable',SID,null) SID from V$SES_OPTIMIZER_ENV where lower(name) like '%isolation%' order by name ) select q1.* ,vs.status,vs.username,vs.OSUSER,vs.MACHINE,vs.TERMINAL,vs.PROGRAM from q1, v$session vs where q1.sid=vs.sid(+);

-- Regards. -- AZ