Channel initiator control information block

Use this topic as a reference for the channel initiator control information block.

The channel initiator control information block contains basic information for this CHINIT, including:

CHINIT job name (qcctjobn)
QSG name if it is in a queue sharing group (qcctqsgn)
Peak number used of current channels (qcctnocc)
Peak number used of active channels (qcctnoac)
MAXCHL - maximum permitted current channels (qcctmxcc)
ACTCHL - maximum permitted active channels (qcctmxac)
TCPCHL - maximum permitted TCP/IP channels (qcctmxtp)
LU62CHL - maximum permitted LU62 channels (qcctmxlu)
31-bit storage used by CHINIT in the extended private region (qcctstus). This information is also provided by the CSQX004I message in the CHINIT job log.
64-bit storage limit available to the CHINIT (qcctslim)
64-bit storage used by CHINIT (qcctstab). This information is also provided by the CSQX004I message in the CHINIT job log.

The format of the channel initiator control information block is described in structure qcct in the C programming language header file thlqual.SCSQC370(CSQDSMFC), and in assembler macro thlqual.SCSQMACS(CSQDQCCS).

You can use this information to see if the number of active channels is approaching the configured maximum value. Note that the number of current and active channels are the values when the record was created. So, between the two intervals there might have been more than this number of channels active.

Channel information from SMF data

Here is an example of channel information from SMF data: [MQ 9.3.5 Feb 2024]


MV4A,MQ27,2023/10/02,11:53:02,VRM:934,
From 2023/10/02,11:52:52 to 2023/10/02,11:53:02, duration 10 seconds.
Peak number used of current channels........... 1
Peak number used of active channels ........... 1
MAXCHL. Max allowed current channels........... 9999
ACTCHL. Max allowed active channels............ 9999
TCPCHL. Max allowed TCP/IP channels............ 9999
LU62CHL. Max allowed LU62 channels............. 200
31-bit storage used............................ 436 MB
64-bit storage limit...........................16384 PB
64-bit storage used............................ 187 MB
64-bit storage free............................16384 PB

You can monitor the storage usage and see whether the value is trending upwards. If the total used is approaching the total storage available, you might be running out of storage, and so might not be able to support many more channels.

If the numbers of active current channels are tending towards the maximum number of channels, you might need to increase the maximum number of channels.