Igor Kromin |   Consultant. Coder. Blogger. Tinkerer. Gamer.

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I've been running a lot of SQL recently that would sometimes get 'stuck' due to the optimiser picking a plan with a full table scan. On a small database this may not be a problem, but when the database has billions of rows and a full table scan that pulls in 100Gb+ of data, the wait is long.

We didn't have Enterprise Manager available, so it was down to doing things manually.


First, to identify the currently running SQLs:
SELECT SID, SERIAL#, SQL_ID
FROM GV$SESSION
WHERE USERNAME IS NOT NULL AND STATUS = 'ACTIVE' AND SQL_ID IS NOT NULL;


Using the output from the above query, we need to find the correct SQL ID. The query below will do that. Use the SQL_ID from the output and replace {sql_id}, these should look something like '1ka9536avjyuc'.
SELECT SQL_TEXT
FROM V$SQL
WHERE SQL_ID = '{sql_id}';


Running two queries is a bit tedious, so simplifying this into one query:
SELECT S.SID, S.SERIAL#, Q.SQL_TEXT
FROM GV$SESSION S, V$SQL Q
WHERE S.USERNAME IS NOT NULL
AND S.STATUS = 'ACTIVE'
AND S.SQL_ID IS NOT NULL
AND Q.SQL_ID = S.SQL_ID;


Now this gives us the SID and SERIAL# that we need to kill the session.

Using the SQL below the session can be terminated, replace the {sid} and {serial#} that corresponds to the query that should be killed. This will kill the entire session, so if the query that is causing trouble is a part of a script, the entire script will lose its connection to the Oracle Database.
ALTER SYSTEM KILL SESSION '{sid},{serial#}';




-i

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