[BUG] — Dubbo plugin performs blocking registry connect / `ReferenceConfig.get()` on the event loop (cache-miss path)

[Aias00]

• severity: Medium-High
• files: shenyu-plugin/shenyu-plugin-proxy/shenyu-plugin-rpc/shenyu-plugin-dubbo/shenyu-plugin-apache-dubbo/src/main/java/org/apache/shenyu/plugin/apache/dubbo/cache/ApacheDubboConfigCache.java:253,282 (reference.get()); lazy-init fallback ApacheDubboProxyService.java:135-140 (initRefN → build → reference.get())
• description: On first request per path or after invalidate/cache expiry, getReferenceConfig calls ReferenceConfig.get() on the calling (event-loop) thread. ReferenceConfig.get() synchronously connects to the registry (Zookeeper/Nacos), resolves providers and builds the GenericService proxy — known blocking, potentially multi-hundred-ms.
• impact: Cold-start / metadata-refresh latency spikes on the Dubbo route; event-loop stalls when Dubbo references are lazily (re)built during traffic or registry flap.
• suggested_fix: Pre-warm references off the event loop (the metadata-sync path already has initRef); ensure lazy init in genericInvoker is removed or moved to Mono.fromCallable(...).subscribeOn(boundedElastic()).
• confidence: High

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Identified during the 2026-08-02 deep re-scan; full list in docs/scan2-2026-08-02/06-medium-tiers.md.

[github-actions]

👋 Hello @yuluo-yx

A new issue has been opened by @Aias00:

• Title: [BUG] — Dubbo plugin performs blocking registry connect / ReferenceConfig.get() on the event loop (cache-miss path)
• Link: [BUG] — Dubbo plugin performs blocking registry connect / ReferenceConfig.get() on the event loop (cache-miss path) #6792

Please review when you have time. Thank you! 🙏