How MID Server gets work from the queue

The MID Server subscribes to messages published by the Asynchronous Message Bus (AMB) Client, which notifies the MID Server that it has pending tasks in the ECC queue.

The MID Server opens a persistent connection to the instance through AMB and listens on the /mid/server/<mid_sys_id> AMB channel. When an output record is inserted into the Queue [ecc_queue] table, an AMB message is sent to the MID Server's channel. The MID Server receives this message and immediately polls the ecc_queue table for work.

The MID Server polls the ECC queue on the interval defined in the mid.poll.time configuration parameter, regardless of AMB message activity. The default polling interval is set to 40 seconds, but can be reconfigured. This polling of the ECC queue at a regular interval is done in case the AMB connection is dropped.

Figure 1. MID Server ECC queue polling process
MID Server ECC queue polling process