Aias00 opened a new issue, #6565:
URL: https://github.com/apache/shenyu/issues/6565
## Description
`CACHE` is a `WindowTinyLFUMap` built with `maximumSize =
Integer.MAX_VALUE`, which disables size-based eviction entirely; there is no
`expireAfterWrite`. The class comment at line 148 even acknowledges OOM risk
yet configures an unbounded size. `MAPPING` (`ConcurrentMap<String,
Set<String>>`) is populated by `initCache`: for wildcard metadata paths the
reverse-mapping `ConcurrentSkipListSet` under each `metaPath` collects every
distinct request path ever matched. `clean(key)` removes CACHE entries but
**never clears the Set itself and never removes it from MAPPING**;
`remove(MetaData)` only calls `clean(path)`.
## Location
```
shenyu-plugin-base/.../cache/MetaDataCache.java:48 (CACHE), 53 (MAPPING),
99-107 (clean), 147-157 (initCache)
```
## Impact
`MetaDataCache.obtain(path)` is called every request from the global plugin
and divide/context-path/rewrite plugins. High-cardinality request paths (e.g.
`/api/users/{userId}` with millions of distinct IDs) cause monotonic, unbounded
heap growth in both CACHE and the MAPPING `ConcurrentSkipListSet` (memory-heavy
per entry) that survives metadata refreshes. Slow OOM over days/weeks for
public-facing REST gateways.
## Suggested fix
Set a real configurable `maximumSize` and `expireAfterAccess`; in
`clean(key)`, after removing CACHE entries, also `MAPPING.get(key).clear()` and
`MAPPING.remove(key)`.
## Related existing issue(s)
#6506 is the CachePlugin (response caching); this is the metadata path
cache. #6479 is discovery-upstream cache staleness; this is selector/metadata
cache growth.
_Identified during the 2026-08-02 audit; full list in
[`docs/issue-candidates-2026-08-02.md`](docs/issue-candidates-2026-08-02.md)._
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