Monitoring Temporary Tablespace Usage in Oracle Database

Lists the Contents of the Temporary Tablespace(s), Including Details About Each Temporary Object and Its Associated Session

Sample SQL Command

 1set pages 999 lines 100
 2col username format a15
 3col mb format 999,999
 4select  su.username
 5,       ses.sid 
 6,       ses.serial#
 7,       su.tablespace
 8,       ceil((su.blocks * dt.block_size) / 1048576) MB
 9from    v$sort_usage    su
10,       dba_tablespaces dt
11,       v$session ses
12where   su.tablespace = dt.tablespace_name
13and     su.session_addr = ses.saddr

Sample Oracle Output:

1USERNAME               SID    SERIAL# TABLESPACE                            MB
2--------------- ---------- ---------- ------------------------------- --------
3REP_USER               117       1243 TEMP                                  25
4APP_DATA_OWNER          81         32 TEMP                                 231
62 rows selected.


  • To monitor and analyze temporary data usage within the database, helping to identify potential performance bottlenecks or excessive resource consumption.
  • To gather information about individual sessions using temporary tablespaces, aiding in troubleshooting queries or optimizing overall resource allocation.


  1. set pages 999 lines 100: Increases the output buffer and number of displayed lines to accommodate potentially large results.
  2. col username format a15: Sets the display width for the "username" column for better readability.
  3. col mb format 999,999: Formats the "MB" column with commas for easier viewing of large sizes.
  4. select ...: Retrieves data from three views:
    • v$sort_usage: Provides information about temporary segments used for sorting operations.
    • dba_tablespaces: Contains details about tablespaces, including the temporary ones.
    • v$session: Offers information about active database sessions.
  5. where ...: Filters the results to include only rows where:
    • The temporary object's tablespace matches the tablespace name in dba_tablespaces.
    • The session address using the temporary object matches the associated session in v$session.
  6. order by ...: The output is not explicitly ordered in this code snippet. You can add an order by clause to sort the results based on specific columns like username, size, or session ID.

Key Points:

  • This code requires appropriate privileges to access the referenced views (typically DBA or SYSDBA).
  • The displayed size uses the block size configured for the tablespace(s). Ensure you understand the block size conversion to megabytes (MB) for accurate interpretation.
  • This code captures a snapshot of temporary usage at the query execution time. Consider monitoring or scripting repeated execution for dynamic insights.
  • Analyzing the size, user, and session information can help identify inefficiencies, performance issues, or potential security concerns related to temporary data usage.

Insights and Explanations:

  • Monitoring temporary tablespace usage is crucial for ensuring efficient resource allocation and preventing performance bottlenecks. This code provides a starting point for further analysis and investigation.
  • Correlating session IDs with user information can help pinpoint specific users or queries contributing to high temporary data usage.
  • Consider combining this code with other queries or tools to track changes over time, analyze specific sessions, or identify long-running temporary objects.

Remember to use this code responsibly, understand its limitations, and tailor it to your specific monitoring needs and database configuration.

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