Attributes for changing configuration information on IBM i

Use this information to understand the configuration information stanzas.

• The AllQueueManagers stanza
• The DefaultQueueManager stanza
• The ExitProperties stanza
• The QueueManager stanza

There are also two stanzas associated with API exits, ApiExitCommon and ApiExitTemplate. For details on using these, see Configure API exits.

The AllQueueManagers stanza

• The path to the qmgrs directory where the files associated with a queue manager are stored
• The path to the executable library
• The method for converting EBCDIC-format data to ASCII format

In the descriptions of the stanzas, the value underlined is the default value and the | symbol means or.

DefaultPrefix= directory_name

The path to the qmgrs directory, within which the queue manager data is kept. If we change the default prefix for the queue manager, we must replicate the directory structure that was created at installation time. In particular, create the qmgrs structure. Stop IBM MQ before changing the default prefix, and restart IBM MQ only after moving the structures to the new location and changing the default prefix.

As an alternative to changing the default prefix, we can use the environment variable MQSPREFIX to override the DefaultPrefix for the CRTMQM command.

DefaultEphemeralPrefix= directory_name

This attribute specifies the path to the directory, within which the queue manager ephemeral data is kept, such as IPC sockets, and is used only to set the EphemeralPrefix of a queue manager when a queue manager is created. In addition, create the directory yourself if we change the default value.

We must create the ephemeral data directory with permissions that allow the IBM MQ group access to write to that directory.

We can use the environment variable MQ_EPHEMERAL_PREFIX to override the DefaultEphemeralPrefix for the crtmqm command.

Because of operating system restrictions, the default ephemeral prefix is restricted to 24 characters on IBM i.

ConvEBCDICNewline=NL_TO_LF|TABLE|ISO

EBCDIC code pages contain a newline (NL) character that is not supported by ASCII code pages, although some ISO variants of ASCII contain an equivalent.

Use the ConvEBCDICNewline attribute to specify the method IBM MQ is to use when converting the EBCDIC NL character into ASCII format.

NL_TO_LF

Convert the EBCDIC NL character (X'15') to the ASCII line feed character, LF (X'0A'), for all EBCDIC to ASCII conversions.

NL_TO_LF is the default.

TABLE

Convert the EBCDIC NL character according to the conversion tables used on IBM i for all EBCDIC to ASCII conversions.

Note that the effect of this type of conversion can vary from language to language .

ISO

Specify ISO if we want:

• ISO CCSIDs to be converted using the TABLE method
• All other CCSIDs to be converted using the NL_TO_CF method.

Possible ISO CCSIDs are shown in Table 1.

CCSID	Code Set
819	ISO8859-1
912	ISO8859-2
915	ISO8859-5
1089	ISO8859-6
813	ISO8859-7
916	ISO8859-8
920	ISO8859-9
1051	roman8

If the ASCII CCSID is not an ISO subset, ConvEBCDICNewline defaults to NL_TO_LF.

The DefaultQueueManager stanza

The DefaultQueueManager stanza specifies the default queue manager for the node.

Name= default_queue_manager

The default queue manager processes any commands for which a queue manager name is not explicitly specified. The DefaultQueueManager attribute is automatically updated if you create a new default queue manager. If you inadvertently create a new default queue manager and then want to revert to the original, we must alter the DefaultQueueManager attribute manually.

The ExitProperties stanza

The ExitProperties stanza specifies configuration options used by queue manager exit programs.

In the descriptions of the stanzas, the value underlined is the default value and the | symbol means or.

CLWLMode= SAFE|FAST

The cluster workload exit, CLWL, specifies which cluster queue in the cluster is to be opened in response to an MQI call (for example: MQOPEN or MQPUT). The CLWL exit runs either in FAST mode or SAFE mode depending on the value you specify on the CLWLMode attribute. If we omit the CLWLMode attribute, the cluster workload exit runs in SAFE mode.

SAFE

Run the CLWL exit in a separate process to the queue manager. This is the default. If a problem arises with the user-written CLWL exit when running in SAFE mode, the following happens:

• The CLWL server process (amqzlwa0) fails
• The queue manager restarts the CLWL server process
• The error is reported in the error log. If an MQI call is in progress, you receive notification in the form of a bad return code.

The integrity of the queue manager is preserved.

Note: Running the CLWL exit in a separate process might have a detrimental effect on performance.

FAST

Run the cluster exit inline in the queue manager process.

Specify this option improves performance by avoiding the overheads associated with running in SAFE mode, but does so at the expense of queue manager integrity. Run the CLWL exit in FAST mode only if we are convinced that there are no problems with your CLWL exit, and we are particularly concerned about performance overheads.

If a problem arises when the CLWL exit is running in FAST mode, the queue manager fails and you run the risk of compromising the integrity of the queue manager.

The QueueManager stanza

There is one QueueManager stanza for every queue manager. These attributes specify the queue manager name and the name of the directory containing the files associated with that queue manager. The name of the directory is based on the queue manager name, but is transformed if the queue manager name is not a valid file name.

See Understand IBM MQ for IBM i queue manager library names for more information about name transformation.

Name= queue_manager_name

The name of the queue manager.

Prefix= prefix

Where the queue manager files are stored. By default, this is the same as the value specified on the DefaultPrefix attribute of the AllQueueManager stanza in the mqs.ini file.

Directory= name

The name of the subdirectory under the prefix\QMGRS directory where the queue manager files are stored. This name is based on the queue manager name, but can be transformed if there is a duplicate name, or if the queue manager name is not a valid file name.

Library= name

The name of the library where IBM i objects pertinent to this queue manager, for example, journals and journal receivers, are stored. This name is based on the queue manager name, but can be transformed if there is a duplicate name, or if the queue manager name is not a valid library name.

Parent topic: Change configuration information on IBM i