CachedBlobBackend held its single tokio::Mutex<LruCache> across filesystem
syscalls, serializing every concurrent cache operation behind one lock:
- get_blob_stream / get_blob_range_stream: held across File::open()/seek()
- delete_blob: held across remove_file()
- initialize: held across the full cache-dir walk
- eviction (insert + fetch paths): held across remove_file() loops
Now the lock only guards the in-memory LRU. Presence checks bump recency
and release the guard before touching the filesystem (a vanished file falls
through to the existing fetch-and-cache path, covering the race), and
eviction selects victims under the lock then unlinks them after releasing
it. The duplicated eviction loop is extracted into
CachedRef::collect_evictions.
db: set test_before_acquire(false). With warm min_connections and a bounded
max_lifetime, the liveness ping sqlx issues on every acquire() costs more
than the rare dead connection it catches; stale sockets surface as a query
error and the pool recycles them either way.
https://claude.ai/code/session_01UtfkS3nZF1vrF5jNAps6wV
Claude