perf(android): Init shake detector off the main thread - #5784
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runningcode merged 4 commits intoJul 21, 2026
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FeedbackShakeIntegration.register() resolved the accelerometer via SensorManager synchronously on the calling thread, which under auto-init is the main thread. On a Pixel 10 this first SensorManager access measured ~1.75ms, making it the single most expensive integration in the Sentry.init register loop. Submit the pre-warm init() to the executor service instead. start() already re-runs the idempotent init() on demand, so shake detection still works if an activity resumes before the warm-up completes. SentryShakeDetector's lifecycle methods are now synchronized so the executor warm-up and a main-thread start() cannot race on the sensor fields. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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July 17, 2026 15:14
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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runningcode
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July 17, 2026 15:20
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Performance metrics 🚀
Baseline results on branch: mainStartup times
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Previous results on branch: no/feedbackshake-register-asyncStartup times
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runningcode
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July 20, 2026 07:09
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I think the bot comment needs addressing but LGTM otherwise, pre-approving
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…618) A warm-up init submitted to the executor could be drained after the integration's close() ran, since integrations shut down before the executor. That re-resolved the sensor and leaked a HandlerThread. Guard init()/start() with a closed latch so a late warm-up is a no-op. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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The closed latch added to neutralize a warm-up drained after close() was permanent, so re-registering the same integration (e.g. a second Sentry.init reusing the same options) left shake detection off with no recovery. register() now re-arms the detector via reopen(), which the stale-warm-up path (init()) deliberately does not, preserving the drain-after-close guard. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Summary
FeedbackShakeIntegration.register() resolved the accelerometer via SensorManager synchronously on the calling thread — the main thread under auto-init. On a Pixel 10 (Android 17, release build) this first SensorManager access measured ~1.75 ms, making it the single most expensive integration in the Sentry.init register loop (the loop total was ~5.1 ms).
This moves the pre-warm shakeDetector.init(...) onto options.getExecutorService(). SentryShakeDetector.start() already re-runs the idempotent init() on demand, so shake detection still works if an activity resumes before the warm-up finishes. SentryShakeDetector's lifecycle methods (init/start/stop/close) are now synchronized so the executor warm-up and a main-thread start() cannot race on the sensor fields.
Measurement (Pixel 10, release, median of 10 cold starts)
Follow-up to JAVA-618. Companion PR defers the other big synchronous item (NDK init).