What applications run on an IBM MQ MQI client?
The full MQI is supported in the client environment.
This enables almost any IBM MQ application to be configured to run on an IBM MQ MQI client system by linking the application on the IBM MQ MQI client to the MQIC library, rather than to the MQI library. The exceptions are:- MQGET with signal
- An application that needs sync point coordination with other resource managers must use an extended transactional client
If read ahead is enabled, to improve non persistent messaging performance, not all MQGET options are available. The table shows the options that are allowed, and whether they can be altered between MQGET calls.
| Values | Permitted when read ahead is enabled and can be altered between MQGET calls | Permitted when read ahead is enabled but cannot be altered between MQGET calls 1 | MQGET options that are not permitted when read ahead is enabled 2 |
|---|---|---|---|
| MQGET MD values |
MsgId 3 CorrelId 3 |
Encoding CodedCharSetId |
|
| MQGET MQGMO options |
MQGMO_WAIT MQGMO_NO_WAIT MQGMO_FAIL_IF_QUIESCING MQGMO_BROWSE_FIRST 4 MQGMO_BROWSE_NEXT 4 MQGMO_BROWSE_MESSAGE _UNDER_CURSOR 4 |
MQGMO_SYNCPOINT_IF_PERSISTENT MQGMO_NO_SYNCPOINT MQGMO_ACCEPT_TRUNCATED_MSG MQGMO_CONVERT MQGMO_LOGICAL_ORDER MQGMO_COMPLETE_MSG MQGMO_ALL_MSGS_AVAILABLE MQGMO_ALL_SEGMENTS_AVAILABLE MQGMO_MARK_BROWSE_HANDLE MQGMO_MARK_BROWSE_CO_OP MQGMO_UNMARK_BROWSE_CO_OP MQGMO_UNMARK_BROWSE_HANDLE MQGMO_UNMARKED_BROWSE_MSG MQGMO_PROPERTIES_FORCE_MQRFH2 MQGMO_NO_PROPERTIES MQGMO_PROPERTIES_IN_HANDLE MQGMO_PROPERTIES_COMPATIBILITY |
MQGMO_SET_SIGNAL MQGMO_SYNCPOINT MQGMO_MARK_SKIP _BACKOUT MQGMO_MSG_UNDER _CURSOR 4 MQGMO_LOCK MQGMO_UNLOCK |
| MQGMO values | MsgHandle |
- If these options are altered between MQGET calls an MQRC_OPTIONS_CHANGED reason code is returned.
- If these options are specified on the first MQGET call then read ahead is disabled. If these options are specified on a subsequent MQGET call a reason code MQRC_OPTIONS_ERROR is returned.
- The client applications need to be aware that if the MsgId and CorrelId values are altered between MQGET calls messages with the previous values might have already been sent to the client and remain in the client read ahead buffer until consumed (or automatically purged).
- The first MQGET call determines whether messages are to be browsed or got from a queue when read ahead is enabled. If the application attempts to use a combination of browse and get an MQRC_OPTIONS_CHANGED reason code is returned.
- MQGMO_MSG_UNDER_CURSOR is not possible with read ahead. Messages can be browsed or got when read ahead is enabled but not a combination of both.
An application running on an IBM MQ MQI client can connect to more than one queue manager concurrently, or use a queue manager name with an asterisk (*) on an MQCONN or MQCONNX call (see the examples in Connect IBM MQ MQI client applications to queue managers ).
Parent topic: Why use IBM MQ clients?