https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=32573 Bug ID: 32573 Summary: background_jobs_worker.pl should ACK a message before it forks and runs the job Change sponsored?: --- Product: Koha Version: master Hardware: All OS: All Status: NEW Severity: normal Priority: P5 - low Component: Architecture, internals, and plumbing Assignee: koha-bugs@lists.koha-community.org Reporter: kyle@bywatersolutions.com QA Contact: testopia@bugs.koha-community.org Splitting off this functionality from bug 32558. This is the comment that started this discussion: https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=32558#c15
From the O'Reilly book Mobile and Web Messaging:
By default, the STOMP broker will consider the message automatically acknowledged when it is delivered to the consumer. However, there are cases in which the consumer may prefer to explicitly acknowledge the message. It leaves a window of opportunity to determine whether it can handle the message or not. For example, the client needs to write the message payload in a data store. There may be issues with opening a connection to the data store and the client could choose to acknowledge the message only after having successfully written its body to the data store. In case of failure, it will instead nack the message (explicitly refuse to take ownership of it). When the STOMP broker is informed of this negative acknowledgment, it may then decide to deliver the message to another consumer subscribed to the destination or try again some time later depending on its configuration. ---
--- RabbitMQ STOMP plugin supports auto, client, and client-individual subscription headers that affect how ACK on NACK operations work. The auto mode uses automatic acknowledgements. The client mode is manual (client-driven) acknowledgements of multiple messages at once. The client-individual is for message-by-message manual acknowledgement. --- If ACK is meant to be sent post-work, why would automatic acknowledgement exist? The interpretation that an ACK is meant to be sent after handling the processing of a job doesn't make sense. In summary, we should be sending back ACK messages as soon as we've successfully processed ( e.g. read and decoded the data ) of a frame. Only then should we process it. -- You are receiving this mail because: You are watching all bug changes. You are the assignee for the bug.