Performance: Lock Waits (DB2 UDB for UNIX and
Windows) 
The system searches for lock waits indicating that at least one process is locked by the lock on another process. A request waits for a resource (a database table or a row of a table) that is locked exclusively by another user.
You can access the Lock Waits screen by calling the DBA Cockpit and choosing Performance ® Lock Waits in the navigation frame of the DBA Cockpit.
If you want to
display data for the first time, choose 
Refresh. In the Layout field, you can choose whether you want
to display the data in a graphic or in a table.
If you display the data in a table, the following information is displayed:
|
Column |
Description |
|
Appl. Handle Waiting |
Agent handle of the application waiting for the lock to be released |
|
Appl. Name Waiting |
Name of the application waiting for the lock to be released |
|
Appl. Handle Holding |
Agent handle of the application holding the lock |
|
Appl. Name Holding |
Name of the application holding the lock |
|
Lock Waiting |
Lock modes that the waiting application would like to set The following lock modes are possible: · IS: intention share lock · IX: intention exclusive lock · S: share lock · SIX: share with intention exclusive lock · X: exclusive lock · IN: intent none · Z: super exclusive lock · U: update lock · NS: next key share lock · NX: next key exclusive lock · W: weak exclusive lock · NW: next key weak exclusive lock |
|
Lock Holding |
Lock mode held |
|
Lock Object Type |
Type of object to be locked |
|
Table Name |
Table on which/on whose record the lock is held |
You can display
more detailed information by selecting one lock wait in the table and choosing
Details. A detail screen appears with additional
information:
|
Field |
Description |
|
Agent PID Waiting |
Process ID of the coordinator agent of the application waiting for the lock to be released |
|
Client PID Waiting |
Process ID of the application waiting for the lock to be released |
|
Host Name Waiting |
Host name of the server on which the application waiting for the lock to be released is running |
|
Agent PID Holding |
Process ID of the coordinator agent of the application holding the lock |
|
Client PID Holding |
Process ID of the application holding the lock |
|
Host Name Holding |
Host name of the server on which the application holding the lock is running |
|
Table Schema |
Schema to which the table belongs |
|
Tablespace |
Tablespace containing the table concerned |
|
Start Date |
Date when lock was set |
|
Start Time |
Time when lock was set |
Lock wait situations are recognized by DB2. Database parameter LOCKTIMEOUT specifies how many seconds the system must wait before automatically resolving a lock wait situation.
If LOCKTIMEOUT is set to -1, lock wait situations are not resolved.