Blocking Locks Tab
In real-time mode, with the Resource focus on Lock waits, the Blocking Locks tab displays all locks that have occurred and are occurring in the current period. This tool facilitates an at-a-glance, in-depth viewing of system locking activity. Use it to identify sessions causing excessive lock problems.
The default blockers display identifies the blocking sessions
(denoted with 
). The displayed blockers attributes are:
|
Blocker |
Attribute |
|
SID |
SID of the blocking session. Click the SID to drilldown into the blocking session and trace its activity. |
|
Serial |
Serial number identifying the blocking session. |
|
DB User |
Oracle user under which the session is running. |
Expanding the blocking session by clicking on the icon displays the set of individual locks created by the
blocking session. Only locks which actually resulted in a block are included.
The lock icon (
) indicates a currently active lock. The displayed
metrics consist of:
|
Column |
Description |
|
SID |
SID of the blocked session. Click the SID to drilldown into the blocked session and trace its activity. In the case of an active lock, the actual blocked statement can be discovered by looking at the current active cursor in the Open Cursors tab. |
|
Serial |
Serial number identifying the blocked session. |
|
DB User |
Oracle user under which the session is running. |
|
Locked Server PID |
Process ID of the blocked session server process. |
|
Lock Type |
Indicates the Oracle lock type (for example, TX or TM). |
|
Mode Wanted |
Mode in which the blocked session has requested the lock. |
|
Object Wanted |
Database object on which the lock took place. |
|
Lock Time |
Date and time when the blocking began. |
|
Duration in Time Range |
Amount of time the lock took place within the displayed period (denominated in accordance with the totaling method in effect. |