perf: Let HostnameCache worker thread idle out (JAVA-653) - #5817
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Performance metrics 🚀
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| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| d15471f | 369.38 ms | 459.08 ms | 89.70 ms |
| bbc35bb | 324.88 ms | 425.73 ms | 100.85 ms |
| b193867 | 319.59 ms | 403.09 ms | 83.50 ms |
| 62b579c | 299.75 ms | 364.84 ms | 65.09 ms |
| 382d6c1 | 306.85 ms | 368.70 ms | 61.85 ms |
| 48277cd | 320.38 ms | 379.90 ms | 59.52 ms |
| 5b1a06b | 315.40 ms | 353.33 ms | 37.94 ms |
| ee747ae | 415.92 ms | 470.15 ms | 54.23 ms |
| 37ec571 | 366.04 ms | 424.28 ms | 58.23 ms |
| 462dea2 | 277.68 ms | 359.83 ms | 82.15 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| d15471f | 1.58 MiB | 2.13 MiB | 559.54 KiB |
| bbc35bb | 1.58 MiB | 2.12 MiB | 553.01 KiB |
| b193867 | 1.58 MiB | 2.19 MiB | 620.00 KiB |
| 62b579c | 0 B | 0 B | 0 B |
| 382d6c1 | 1.58 MiB | 2.29 MiB | 719.85 KiB |
| 48277cd | 0 B | 0 B | 0 B |
| 5b1a06b | 0 B | 0 B | 0 B |
| ee747ae | 1.58 MiB | 2.10 MiB | 530.95 KiB |
| 37ec571 | 0 B | 0 B | 0 B |
| 462dea2 | 0 B | 0 B | 0 B |
HostnameCache used Executors.newSingleThreadExecutor, whose worker thread stays alive for the life of the process even though the cache refreshes at most once every 5 hours. Use a ThreadPoolExecutor with a keep-alive and allowCoreThreadTimeOut(true) so the thread terminates when idle and is recreated on the next refresh. Keeping a dedicated executor (rather than sharing one) preserves the blocking future.get(1s) timeout behavior. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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📜 Description
HostnameCache's executor stays around for the entire process lifetime (that's howThreadPoolExecutorswork by default) even though the cache only refreshes once every 5 hours. It now uses aThreadPoolExecutor(core = max = 1) with a 30s keep-alive andallowCoreThreadTimeOut(true), so the worker thread self-terminates when idle and is recreated on the next refresh.Alternatively, we can also use an existing executor for this but this is the smallest change here. Let me know if you think we should go that route.
💡 Motivation and Context
Part of reducing the number of threads created by the SDK: JAVA-653.
💚 How did you test it?
There are some new unit tests, but otherwise relying on ART/JVM to do their thing correctly.
📝 Checklist
sendDefaultPIIis enabled.