HardenGetBackout (10-digit signed integer) on IBM i
Whether to maintain an accurate backout count.
| Local | Model | Alias | Remote | Cluster |
|---|---|---|---|---|
| X | X |
For each message, a count is kept of the number of times that the message is retrieved by an MQGET call within a unit of work, and that unit of work later backed out. This count is available in the MDBOC field in the message descriptor after the MQGET call has completed.
The message backout count survives when the queue manager restarts. However, to ensure that the count is accurate, information has to be "hardened" (recorded on disk or other permanent storage device) each time a message is retrieved by an MQGET call within a unit of work for this queue. If this is not done, and a failure of the queue manager occurs together with backout of the MQGET call, the count might not be incremented.
Hardening information for each MQGET call within a unit of work, however, imposes a performance cost, and the HardenGetBackout attribute should be set to QABH only if the count has to be accurate.- On IBM i, the message backout count is always hardened, regardless of the setting of this attribute.
The following values are possible:
- QABH
- Backout count remembered.
Hardening is used to ensure that the backout count for messages on this queue is accurate.
- QABNH
- Backout count might not be remembered.
Hardening is not used to ensure that the backout count for messages on this queue is accurate. The count might therefore be lower than it should be.
To determine the value of this attribute, use the IAHGB selector with the MQINQ call.
Parent topic: Attributes for queues