Oracle DBA Tutorial How to Find and Kill Sessions in Oracle Database

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Welcome to this tutorial on Oracle DBA, where we will explore the process of finding and killing sessions in an Oracle database using SQL Developer. Sessions in Oracle consist of connections to the database by users from specific processes. Killing a session is necessary when the session becomes large and slows down the database. In this article, we will discuss the steps to find and terminate inactive and waiting sessions, ensuring optimal database performance.

Step-by-Step Process:

  1. Logging into SQL Developer: Begin by launching SQL Developer and logging into your Oracle database. Use the following query to obtain a list of usernames:
    SELECT username FROM dba_users;

  2. Connecting to Database: After obtaining the username, establish a connection to the Oracle database using the SQL Developer interface. Download and install SQL Developer if you haven’t already done so. Once connected, run the query below to retrieve the session count:
    SELECT COUNT(*) FROM v$session;
    This query will enable us to identify the number of sessions we have.

  3. Retrieving Session List: Execute the following query to fetch the list of sessions in order to identify the sessions that need to be terminated:
    sql
    SELECT sid, serial#, username, status, state FROM v$session WHERE username NOT IN ('SYS', 'SYSTEM') AND status = 'INACTIVE' AND state = 'WAITING';

  4. Killing Inactive Sessions: Now that we have the list of inactive and waiting sessions, we can proceed to terminate them. Copy the session details from the previous step and execute the following command to kill the sessions:
    sql
    ALTER SYSTEM KILL SESSION '[SID],[SERIAL#]';

    Replace [SID] and [SERIAL#] with the corresponding values from the session list.

  5. Verification: To ensure that the sessions have been terminated successfully, re-run the query from step 3 to check if the inactive sessions have been removed.

By following these steps, you can effectively find and kill sessions in an Oracle database using SQL Developer. This process helps keep your database running smoothly and optimizes its performance by removing unnecessary and inactive sessions.

Key Points:

  • Sessions in Oracle consist of connections to the database by users from specific processes.
  • Killing sessions is necessary to improve database performance when sessions become large and slow down the system.
  • SQL Developer is a powerful tool that can be used to find and terminate sessions in Oracle databases.
  • Start by logging into SQL Developer and connecting to your Oracle database.
  • Execute queries to obtain a list of usernames and check the session count.
  • Retrieve the list of inactive and waiting sessions using the provided query.
  • Terminate the identified sessions by using the ALTER SYSTEM KILL SESSION command.
  • Verify the termination by re-running the query to ensure the inactive sessions have been removed.

Remember to regularly monitor and manage sessions in your Oracle database to maintain optimal performance and prevent any potential issues. Killing inactive sessions helps free up system resources and keeps your database running smoothly.

Thank you for following this tutorial on how to find and kill sessions in Oracle Database using SQL Developer. We hope you found this information helpful and it contributes to your understanding of Oracle DBA practices.