Handle database timeouts in MQTT queue deletion (backport #12317) #12320
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This return value was already possible since a classic queue will return
it during termination if `rabbit_amqqueue:internal_delete/2` fails with
that value.
`rabbit_amqqueue:delete/4` already handles this value and converts it
into a protocol error and channel exit. The other caller (MQTT
processor) will be updated in a child commit.
This commit also replaces eager conversions to protocol errors in
rabbit_classic_queue, rabbit_quorum_queue and rabbit_stream_coordinator:
we should return `{error, timeout}` consistently and not hide it in
protocol errors.
(cherry picked from commit 9627903)
(cherry picked from commit a9c48ef)
`delegate:invoke/2` catches errors but not exits of the delegate process. Another process might query for a classic queue's consumers while the classic queue is being deleted or otherwise terminating and that would result in an exit of the calling process previously. (cherry picked from commit a65ceb6)
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This fixes some crash reports when using MQTT with Khepri, spotted by @mkuratczyk. With an OMQ stresstest:
while a cluster restarts (
make restart-cluster), we would see badmatch errors from matching on{ok, _}forrabbit_queue_type:delete/4and exits for{normal, {gen_server2, call, [Pid, consumers, infinity]}}. That stress test causes queue churn since QoS1 MQTT creates transient exclusive classic queues. Restarting a node leads to very many queues being deleted which can overload Khepri and lead to timeouts.The first commit makes a refactor to have
rabbit_queue_type:delete/4return{error, timeout}for timeout errors.{error, timeout}could already be returned and is handled inrabbit_amqqueue:delete_with/4. This change is just for consistency: in some places we returned aprotocol_errorrecord instead. The second commit handles the{error, timeout}result inrabbit_mqtt_processor.Also included is a fix for
rabbit_amqqueue:consumers/1to catch exits: an exit can happen if another process asks for a classic queue's consumers while it is terminating. (With Khepri the terminate callback can take some time as it callsrabbit_amqqueue:internal_delete/2.)This is an automatic backport of pull request #12317 done by Mergify.