Quorum Queue consumer cancellation fixes #3448
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
If the queue is empty when a consumer is cancelled it would leave the consumer id inside the service queue. If an application subscribes/unsubscibes in a loop from an empty queue this would cause the service queue to never be cleared up. NB: whenever we make a change to how the quorum queue state machien is calculated we need to consider how this effects determinism as during an upgrade different members may calculate a different service queue state. In this case it should be ok as they will eventually converge on the same state once all "dead" consumer ids have been removed from the queue. In any case it should not affect how messages are assigned to consumers.
If this is not done apps that consume/cancel from empty queues in a loop will grow the raft log in an unbounded manner. This could also be the case for the garbage_collect command.
It should be rare that repeated use of these commands would grow the Raft log excessively but just incase we evaluate the release cursors here anyway so that if the queue is empty we may trigger a snapshot anyway.
kjnilsson
changed the title
Contributor
Author
|
Acceptance steps:
|
acogoluegnes
approved these changes
Sep 20, 2021
acogoluegnes
added a commit
that referenced
this pull request
Sep 21, 2021
Quorum Queue consumer cancellation fixes (backport #3448)
Contributor
|
Backported to |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Fixes #3445
If the queue is empty when a consumer is cancelled it would leave the
consumer id inside the service queue. If an application subscribes/unsubscibes
in a loop from an empty queue this would cause the service queue to never be
cleared up.
NB: whenever we make a change to how the quorum queue state machien is
calculated we need to consider how this effects determinism as during an
upgrade different members may calculate a different service queue state.
In this case it should be ok as they will eventually converge on the same
state once all "dead" consumer ids have been removed from the queue.
QQ: emit release cursors after consumer cancel,
purge_nodes,garbage_collectionandupdate_configcommands to ensure that repeated use of these commandsagainst an empty queue will not grow the log excessively.