The Blocking Tree displays a tree view of sessions that are blocking other sessions for Oracle, SQL Server, 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
To view a database's blocking sessions, click the name of the database.
Click the Blocking Sessions tab.
Features of the Database Blocking Tree Window
On the Database Blocking Tree Window you can:
Expand the tree of a blocking session to see the sessions it is blocking
On the Database Sessions window you can see the following information:
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