PHOENIX-7978 Harden replay/forward poll scheduling against wall-clock… - #2598
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PHOENIX-7978 Harden replay/forward poll scheduling against wall-clock…#2598Himanshu-g81 wants to merge 1 commit into
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… and scheduler drift The round-eligibility gate for replication replay/forward becomes eligible when currentTime - lastRoundEndTimestamp >= roundTimeMills + bufferMillis, evaluated on the wall clock. PHOENIX-7813 aligned the scheduler wake to that grid, but the wake is fired on the monotonic clock (System.nanoTime) and was computed with zero margin, so small nanoTime-vs-wall-clock drift could tip a wake just below the boundary and the region server would lose a full (~60s) cycle. Most damaging during planned failover. Two fixes, both in the shared base class ReplicationLogDiscovery (inherited by ReplicationLogDiscoveryReplay and ReplicationLogDiscoveryForwarder): - Epsilon margin on the aligned wake instant: anchor the delay at bufferMillis + epsilon (via Math.floorMod) so the wake lands just after the eligibility boundary rather than exactly on it. New config phoenix.replication.discovery.aligned.delay.epsilon.millis (default 500). - Per-cycle re-anchor: replace scheduleAtFixedRate with a self-rescheduling one-shot chain that recomputes the aligned delay every cycle, re-pinning each wake to the wall-clock grid instead of letting a one-time misalignment persist. Uses a ScheduledThreadPoolExecutor with setExecuteExistingDelayedTasksAfterShutdownPolicy(false) so stop() is deterministic. Each replay cycle is bound to the scheduler generation it was launched on and reschedules only if isRunning && owner == scheduler, preventing a stale in-flight cycle from grafting a second chain onto a new scheduler after a stop()->start() restart (which would otherwise double the effective poll rate). Testing: ReplicationLogDiscoveryTest 48/48 (incl. stale-generation, start()-rollback, and replay/reschedule error-swallow regressions); ReplicationLogDiscoveryReplayTestIT 48/48; StoreAndForwardFailoverIT 1/1; spotless:check green on phoenix-core and phoenix-core-server.
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Problem
The replay/forward round-eligibility gate is evaluated on the wall clock, but PHOENIX-7813
aligned the scheduler wake — fired on the monotonic clock (
System.nanoTime) — to that boundarywith zero margin. Small nanoTime-vs-wall-clock drift can tip a wake just below the boundary,
so the round isn't yet eligible and the region server loses a full (~60s) cycle. Most damaging
during planned failover.
Fix
Both changes live in the shared base class
ReplicationLogDiscovery(inherited byReplicationLogDiscoveryReplayandReplicationLogDiscoveryForwarder):exactly on it. New config
phoenix.replication.discovery.aligned.delay.epsilon.millis(default500).scheduleAtFixedRatewith a self-rescheduling one-shot thatrecomputes the aligned delay every cycle, so drift can't accumulate. Each cycle is bound to its
scheduler generation to avoid double-scheduling after a
stop()→start()restart.