Control channel statistics collection

Use the channel attribute STATCHL to control the collection of channel statistics information. We can also set queue manager attributes to control information collection.

We can enable or disable channel statistics information collection for individual channels, or for multiple channels. To control individual channels, we must set the channel attribute STATCHL to enable or disable channel statistic information collection. To control many channels together, you enable or disable channel statistics information collection at the queue manager level by using the queue manager attribute STATCHL. For all channels that have the channel attribute STATCHL specified with the value QMGR, channel statistics information collection is controlled at the queue manager level.

Automatically defined cluster-sender channels are not IBM MQ objects, so do not have attributes in the same way as channel objects. To control automatically defined cluster-sender channels, use the queue manager attribute STATACLS. This attribute determines whether automatically defined cluster-sender channels within a queue manager are enabled or disabled for channel statistics information collection.

We can set channel statistics information collection to one of the three monitoring levels: low, medium or high. We can set the monitoring level at either object level or at the queue manager level. The choice of which level to use is dependent on the system. Collecting statistics information data might require some instructions that are relatively expensive computationally, so to reduce the impact of channel statistics information collection, the medium and low monitoring options measure a sample of the data at regular intervals rather than collecting data all the time. Table 1 summarizes the levels available with channel statistics information collection:

Level	Description	Usage
Low	Measure a small sample of the data, at regular intervals.	For objects that process a high volume of messages.
Medium	Measure a sample of the data, at regular intervals.	For most objects.
High	Measure all data, at regular intervals.	For objects that process only a few messages per second, on which the most current information is important.

To change the value of the channel attribute STATCHL, use the MQSC command, ALTER CHANNEL and specify the parameter STATCHL.

To change the value of the queue manager attribute STATCHL, use the MQSC command, ALTER QMGR and specify the parameter STATCHL.

To change the value of the queue manager attribute STATACLS, use the MQSC command, ALTER QMGR and specify the parameter STATACLS.

The channel attribute, STATCHL, can have the following values:

LOW: Channel statistics information is collected with a low level of detail.
MEDIUM: Channel statistics information is collected with a medium level of detail.
HIGH: Channel statistics information is collected with a high level of detail.
OFF: Channel statistics information is not collected for this channel.
QMGR: The channel attribute is set as QMGR. The collection of statistics information for this channel is controlled by the value of the queue manager attribute, STATCHL.
This is the default value.

On z/OS systems, enabling this parameter simply turns on statistics data collection, regardless of the value you select. Specifying LOW, MEDIUM, or HIGH makes no difference to your results. This parameter must be enabled in order to collect channel accounting records.

The queue manager attribute, STATCHL, can have the following values:

LOW: Channel statistics information is collected with a low level of detail, for all channels that have the channel attribute STATCHL set as QMGR.
MEDIUM: Channel statistics information is collected with a medium level of detail, for all channels that have the channel attribute STATCHL set as QMGR.
HIGH: Channel statistics information is collected with a high level of detail, for all channels that have the channel attribute STATCHL set as QMGR.
OFF: Channel statistics information is not collected for all channels that have the channel attribute STATCHL set as QMGR.
This is the default value.
NONE: The collection of channel statistics information is disabled for all channel, regardless of the channel attribute STATCHL.

The queue manager attribute, STATACLS, can have the following values:

LOW: Statistics information is collected with a low level of detail for automatically defined cluster-sender channels.
MEDIUM: Statistics information is collected with a medium level of detail for automatically defined cluster-sender channels.
HIGH: Statistics information is collected with a high level of detail for automatically defined cluster-sender channels.
OFF: Statistics information is not collected for automatically defined cluster-sender channels.
QMGR: The collection of statistics information for automatically defined cluster-sender channels is controlled by the value of the queue manager attribute, STATCHL.
This is the default value.

For example, to enable statistics information collection, with a medium level of detail, for the sender channel QM1.TO.QM2, use the following MQSC command:

ALTER CHANNEL(QM1.TO.QM2) CHLTYPE(SDR) STATCHL(MEDIUM)

To enable statistics information collection, at a medium level of detail, for all channels that specify the channel attribute STATCHL as QMGR, use the following MQSC command:

ALTER QMGR STATCHL(MEDIUM)

To enable statistics information collection, at a medium level of detail, for all automatically defined cluster-sender channels, use the following MQSC command:

ALTER QMGR STATACLS(MEDIUM)

Parent topic: Statistics information collection