DB2 Monitor switches

In order for AQT to display the Snapshot Monitor information, the Monitor flags need to be switched on. There are two ways in which this can be done:

switch the flags on permanently. This is done by setting some flags in the DBM CFG (Database Manager Configuration)
switch on the flags temporarily. This is done by issuing the update monitor switches command .

A summary of the flags, and how they are switched on, is as follows:

Monitor Element	Switch on Permanently	Switch on Temporarily
UOW	update dbm cfg using dft_mon_uow on	update monitor switches using uow on
Statement	update dbm cfg using dft_mon_stmt on	update monitor switches using statement on
Timestamp	update dbm cfg using dft_mon_timestamp on	update monitor switches using timestamp on
Lock	update dbm cfg using dft_mon_lock on	update monitor switches using lock on
Bufferpool	update dbm cfg using dft_mon_bufpool on	update monitor switches using bufferpool on
Table	update dbm cfg using dft_mon_table on	update monitor switches using table on
Sort	update dbm cfg using dft_mon_sort on	update monitor switches using sort on

These commands are run through the DB2 Command Window. Any changes to the dbm cfg only come into effect when the database manager instance is next started, and this will apply to all databases within that instance.

When the flags are switched on temporarily, they are only in effect for the duration of the task that issued the commands. So if you switch them on using a DB2 Command Window, they will be switched off when you close the Command window.

Switching on the Monitor Switches using AQT

Within the System Monitor, you can go View > DB2 Monitor Switches. This will take you to a window which shows you the current state of the switches. You can change them then click on Update.

DB2 doesn't provide an easy mechanism for programs (such as AQT) to change the monitor switches. While there is an API call, this is difficult to use. Instead, AQT changes the monitor switches by opening a DB2 Command Window and issuing the appropriate update monitor switches command.

this command requires an Instance Attachment (not just a database connection). AQT will prompt you for the name of the instance. If you don't know this:
- you will can find this out by running list database directory in a DB2 command window. This can be done from the Run SQL window with Run > Run as DB2 Command
- if the database is on your machine, the instance name is most probably db2
as discussed earlier, the monitor switches only stay switched on while this db2 command window remains open. Only close this once you have finished monitoring the system.

It is hoped that in future releases of DB2, a better mechanism for switching on the monitor flags will be provided.

Further Comment

During testing of the System Monitor, it was found that the monitor information was sometimes not displayed when the switches were set on using the update monitor switches command. It is not known why this is the case. The monitor information displayed much more reliably when the monitor switches were set on in the dbm cfg.