Hello, I am trying to use PIP-105 and I found out that we are missing a few little things to cover my user case. In my case I have two consumers who compete on the same SHARED subscription with a "message filter". The filter is passed as Consumer metadata.
When you have two Consumers connected on the Subscription the dispatcher prepares to send the message to one consumer at a time. The Message goes through the EntryFilter that decides if the Entry matches the requirements of the Consumer. - if the message matches the consumer then it returns ACCEPT - if the message does not match the consumer then it has to be rescheduled (RESCHEDULE) With this small extension to PIP-105 we can cover this simple scenario without the need to introduce a new Dispatcher policy I sent out a patch with the implementation and a test case that shows my usecase https://github.com/apache/pulsar/pull/15391 Introducing RESCHEDULE needs some level of discussion here. With PIP-105 we are anticipating in the broker a decision that the Consumer would take when the Message is already dispatched to the application: A) ignore the message: acknowledge immediately, without processing. (REJECT) B) postpone the message (or let it be processed from another consumer): negatively acknowledge immediately, without processing. (RESCHEDULE) With the initial implementation of PIP-105 we are covering case A, and with my proposal I want to give the opportunity to implement case B. The only point that is not covered by my proposal is that the NACK on the client happens only after a delay on the client, and this has some side effects. In fact that "delay" from the client allows the dispatcher to read more entries because it thinks that the message has been dispatched successfully, and it is allowed to move forward. I would prefer to start a separate discussion for this "problem", that is in part related to how we deal with messages to be replayed and it is not strictly related to my PR. Cheers Enrico
