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Document ID:768
Subject:How to kill/terminate a session in Oracle
Creation date:7/29/09 2:57 PM
Last modified on:7/29/09 2:57 PM


Sessions can be killed from within WinSQL using the ALTER SYSTEM KILL SESSION syntax.

First identify the offending session as follows:

SELECT s.sid,
FROM   v$session s;

This query will result in a similar result.

The SID and SERIAL# values of the relevant session can then be substituted into the following statement:


In some situations the Oracle.exe is not able to kill the session immediately. In these cases the session will be "marked for kill". It will then be killed as soon as possible.

Issuing the ALTER SYSTEM KILL SESSION command is the only safe way to kill an Oracle session. If the marked session persists for some time you may consider killing the process at the operating system level. However, this is not recommended as it is dangerous and can lead to instance failures.

It is possible to force the kill by adding the IMMEDIATE keyword:


User comments

Posted by no good on 11/12/15 1:24 AM

I can't kill the active session using the IMMEDIATE keyword

Posted by vasan on 3/5/11 12:13 AM

i am not a DBA. so i could not kill the session as the session is hanged. please tell me how to kill an user session

Posted by harsha on 2/18/13 7:28 AM

how to know,which session is for which operation?

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