Nonpersistent message speed (NPMSPEED)

This attribute specifies the speed at which nonpersistent messages are to be sent.

Possible values are:

NORMAL

Nonpersistent messages on a channel are transferred within transactions.

FAST

Nonpersistent messages on a channel are not transferred within transactions.

The default is FAST. The advantage of this is that nonpersistent messages become available for retrieval far more quickly. The disadvantage is that because they are not part of a transaction, messages might be lost if there is a transmission failure or if the channel stops when the messages are in transit. See Safety of messages. Notes:

1. If the active recovery logs for IBM MQ for z/OS® are switching and archiving more frequently than expected, given that the messages being sent across a channel are non-persistent, setting NPMSPEED(FAST) on both the sending and receiving ends of the channel can minimize the SYSTEM.CHANNEL.SYNCQ updates.
2. If you are seeing high CPU usage relating to updates to the SYSTEM.CHANNEL.SYNCQ, setting NPMSPEED(FAST) can significantly reduce the CPU usage.

This attribute is valid for channel types of:

• Sender
• Server
• Receiver
• Requester
• Cluster sender
• Cluster receiver