QQ: fix bug when subscribing using an already existing consumer tag #9158
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mkuratczyk
approved these changes
Aug 23, 2023
kjnilsson
changed the title
When subscribing using a consumer tag that is already in the quorum queues state (but perhaps with a cancelled status) and that has pending messages the next_msg_id which is used to initialise the queue type consumer state did not take the in flight message ids into account. This resulted in some messages occasionally not being delivered to the clint and thus would appear stuck as awaiting acknowledgement for the consumer. When a new checkout operation detects there are in-flight messages we set the last_msg_id to `undefined` and just accept the next message that arrives, irrespective of their message id. This isn't 100% fool proof as there may be cases where messages are lost between queue and channel where we'd miss to trigger the fallback query for missing messages. It is however much better than what we have atm. NB: really the ideal solution would be to make checkout operations async so that any inflight messages are delivered before the checkout result. That is a much bigger change for another day.
kjnilsson
changed the title
|
Cool, I've run multiple tests with the second version of the fix and could not reproduce neither missed nor duplicated messages. |
michaelklishin
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Aug 23, 2023
QQ: fix bug when subscribing using an already existing consumer tag (backport #9158)
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When subscribing using a consumer tag that is already in the quorum
queues state (but perhaps with a cancelled status) and that has
pending messages the next_msg_id which is used to initialise the
queue type consumer state did not take the in flight message ids into
account. This resulted in some messages occasionally not being delivered
to the clint and thus would appear stuck as awaiting acknowledgement
for the consumer.
When a new checkout operation detects there are in-flight messages
we set the last_msg_id to
undefinedand just accept the next messagethat arrives, irrespective of their message id. This isn't 100% fool proof
as there may be cases where messages are lost between queue and channel
where we'd miss to trigger the fallback query for missing messages.
It is however much better than what we have atm.
NB: really the ideal solution would be to make checkout operations
async so that any inflight messages are delivered before the checkout
result. That is a much bigger change for another day.