Hi,

Auto Queue Manager

This checkbox is only valid for Standard Queue Mode agents.

This box is checked by default, which enables the Queue Manager (AQM).  When AQM is enabled, then when a queue entry is retrieved for processing by the agent activity, the system locks that entry until a commit or rollback occurs at the end of processing.  (This allows one agent/node to have exclusive rights to that queue entry; no agent on another node can process it.)  If some kind of issue occurs (like the agent can’t get a lock on the work object), the task is re-queued automatically and can be set up to try again.

If AQM is disabled, then the system immediately removes entries from the agent queue, instead of locking them and leaving them in the database table.  When QM is disabled, the system performs the commits or rollbacks on the items being processed, but the queue entry does not persist in the database.  If a rollback occurs, that entry is now gone and cannot be requeued. 

As a best practice, leave AQM enabled for all agents in Standard mode

https://docs-previous.pega.com/system-administration/how-agent-queues-work

Thank You