The blocking tree displays a tree view of sessions that are blocking other sessions for Oracle, SQL Server, SAP HANA, Sybase ASE, and DB2. You can use the blocking tree to determine the cause of deadlocks.

Access the Database Blocking Sessions Window

To access the Database Topology window:

1. To view a database's blocking sessions, click the name of the database.
2. Click the Blocking Sessions tab.

Database Blocking Tree Window Features

From the Database Blocking Tree window you can expand the tree of a blocking session to see the sessions it is blocking.

From the Database Sessions window, you can view:

• Session ID: the Session ID of the sessions causing the block, and the sessions being blocked
• Client: the names of the machines where the session is blocked
• User: the user of the blocked session
• Query: the query that is blocked or causing the block
  
• Blocked Object: the object that is blocked
• First occurrence of block: the time that the block first occurred in the specified time range
• Block Duration: the amount of time that the session was blocked or causing the block