kv: acquire Replica shared mutex in tryGetOrCreateReplica#74356
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craig[bot] merged 1 commit intocockroachdb:masterfrom Jan 3, 2022
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kv: acquire Replica shared mutex in tryGetOrCreateReplica#74356craig[bot] merged 1 commit intocockroachdb:masterfrom
craig[bot] merged 1 commit intocockroachdb:masterfrom
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This commit switches the common path in `tryGetOrCreateReplica` from grabbing the Replica mutex in an exclusive mode to grabbing it in a shared mode. The common path in `tryGetOrCreateReplica` does not mutate the Replica, so there's no need for the stronger lock. The locking in `setLastReplicaDescriptors` showed up in a mutex profile under a write-heavy workload. It was responsible for **2.06%** of mutex wait time. Grabbing the mutex was probably also slowing down Raft request processing, as the exclusive lock acquisition had to wait for other read locks to be dropped.
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Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status:complete! 0 of 0 LGTMs obtained (waiting on @erikgrinaker)
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TFTR! bors r=tbg |
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This commit switches the common path in
tryGetOrCreateReplicafromgrabbing the Replica mutex in an exclusive mode to grabbing it in a
shared mode. The common path in
tryGetOrCreateReplicadoes not mutatethe Replica, so there's no need for the stronger lock.
The locking in
setLastReplicaDescriptorsshowed up in a mutex profileunder a write-heavy workload. It was responsible for 2.06% of mutex
wait time. Grabbing the mutex was probably also slowing down Raft
request processing, as the exclusive lock acquisition had to wait for
other read locks to be dropped.