Adjusting Resource Use by Specific Sessions

As you monitor the database server, you might see that certain sessions require resource-use tuning. For a specified session, onmode commands let you set new values for PDQPRIORITY, set the schedule level, and kill all current queries.

For information on the onmode utility, see the IBM Informix: Extended Parallel Server Administrator's Reference.

Resetting PDQPRIORITY

To specify a new PDQPRIORITY value for a specific session, use the onmode utility with the following syntax:

>>-onmode-- -q--pdqpriority--sessionid--+-----------+--high_value-><
                                        '-low_value-'

For example, to set the PDQPRIORITY value for session 1.35 to a range between 30 and 60, enter the following command:

onmode -q pdqpriority 1.25 30 60 

To set only a maximum PDQPRIORITY value of 60, enter

onmode -q pdqpriority 1.25 60

This onmode command changes the PDQPRIORITY value for all statements that the session submits, including statements already in the Wait queue, unless the queries were submitted when the IMPLICIT_PDQ environment option was in effect. For more information about the PDQPRIORITY parameter, refer to Managing Memory Allocation for a Single Query.

Resetting the Schedule Level

Use onmode -q schlevel sessionid value to reset the schedule level for a specific session. For example, enter onmode -q schlevel 1.35 75 to change the schedule level to 75 for session 1.35.

This onmode command changes the schedule level for all statements that the session submits, including statements already in the Wait queue. For more information about the SCHLEVEL parameter, see Setting Schedule Levels.

Stopping Queries

You can kill all queries that are currently executing and in the wait queue for a specific session, but leave the session active. Use the onmode -q intr sessionid command. For example, to kill all queries for session 1.35, enter onmode -q intr 1.35.