feat(messagequeue): split partition discovery cadence from polling - #528
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## Summary ### Why? Partition discovery, lease acquisition, and worker reconciliation all run on the message-poll ticker (`PollIntervalMs`, 100ms default). Discovery drives topic-wide work every tick — a `DISTINCT partition_key` scan, an active-subscriber read, self-lease reads, and lease-acquisition probes — whose query volume multiplies with subscribers × topics at 10x/sec, even though its outcome only changes when membership or the partition set changes. Message polling needs 100ms latency; discovery does not. ### What? New `PartitionDiscoveryIntervalMs` subscription config (default 1s) drives the supervisor's discovery ticker; `PollIntervalMs` continues to drive per-partition message polling unchanged. This cuts discovery-driven query volume ~10x at the default settings. The accepted trade-off is that a brand-new partition's first message now waits up to the discovery interval (1s) before a worker picks it up; messages on already-owned partitions are unaffected. Integration test configs pin discovery to 100ms so lease-handoff and rebalance convergence assertions stay fast. ## Test Plan - ✅ Full Docker integration suite (`bazel test //test/integration/extension/messagequeue/...`) — discovery-latency-sensitive tests (empty-topic wake-up, rebalance convergence, crash recovery) pass with the new cadence.
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Summary
Why?
Partition discovery, lease acquisition, and worker reconciliation all run on the message-poll ticker (
PollIntervalMs, 100ms default). Discovery drives topic-wide work every tick — aDISTINCT partition_keyscan, an active-subscriber read, self-lease reads, and lease-acquisition probes — whose query volume multiplies with subscribers × topics at 10x/sec, even though its outcome only changes when membership or the partition set changes. Message polling needs 100ms latency; discovery does not.What?
New
PartitionDiscoveryIntervalMssubscription config (default 1s) drives the supervisor's discovery ticker;PollIntervalMscontinues to drive per-partition message polling unchanged. This cuts discovery-driven query volume ~10x at the default settings. The accepted trade-off is that a brand-new partition's first message now waits up to the discovery interval (1s) before a worker picks it up; messages on already-owned partitions are unaffected. Integration test configs pin discovery to 100ms so lease-handoff and rebalance convergence assertions stay fast.Test Plan
bazel test //test/integration/extension/messagequeue/...) — discovery-latency-sensitive tests (empty-topic wake-up, rebalance convergence, crash recovery) pass with the new cadence.Issues