Oracle freezes when updating a table

Question

I am updating a table with an expression

update asdf123 set state='Rlzd' where documentname = '11212121212' and superseded = '-'; 

But it hangs endlessly.

I checked the session, got the hanged session, and then killed it, and the previous session was killed. The same situation is happening again.

What could be the reason?

Answer 1

I think you killed a blocked session (your session) Use something like this to find a blocking session:

 SELECT s.blocking_session, s.sid, s.serial#, s.seconds_in_wait FROM v$session s WHERE blocking_session IS NOT NULL 

See other ways to find them: http://www.oraclerecipes.com/monitoring/find-blocking-sessions/