Out of Sequence Events
Sometimes messages arrive in Access History out of chronological order. This can happen if there is an error in processing that makes it need to be requeued or if there are multiple consumers and one somehow completes processing a newer message faster than another consumer completes processing an older message. When this happens, the system is set up to properly handle these messages by requeuing the messages in the correct chronological order.
In cases where an image processor entity fails to be processed, the processor handler gives an exception error and the message is requeued for another attempt to be processed. You can configure the redelivery delay and maximum number of redelivery attempts. After the message exceeds the number of redelivery attempts, it is discarded and sent to the dead letter queue. See Configuring Access History.
Occasionally, due to bad data, there is no way to process a message. In that case, it is discarded, logged in the discarded messages log file as INFO, and sent to a dead letter queue.
To allow the timeline to show discarded messages, an optional event called DiscardedMessage can be enabled via the Debug page. The default value is false, but it can be enabled by setting the following Access History property to true:
<entry key="createDiscardedMessageEvent" value="false" />
Access History defaults to allow you to audit removed event records. You may disable this functionality from the Audit Configuration page. These records may be created during out-of-sequence processing where a new capture is inserted between two existing captures. The events generated between the two existing captures must be removed and new events generated. See