perf: replace RwLock<HashMap> with DashMap in ChunkedUploadService + decouple disk I/O from lock

Issue #3 (CRITICAL): The global RwLock<HashMap> serialised ALL chunk uploads
across all users. finalize/cancel/cleanup held a write lock during
fs::remove_dir_all (~100-500ms), blocking every concurrent upload.

Changes:
- Replace tokio::sync::RwLock<HashMap<String, UploadSession>> with
  dashmap::DashMap (sharded concurrent map, ~64 shards)
- Operations on independent sessions never contend
- finalize_upload_inner: remove from map (µs), THEN delete temp dir
- cancel_upload_inner: same pattern — disk I/O outside lock
- cleanup_loop: collect expired IDs via lock-free iteration, remove
  from map, THEN delete dirs sequentially with no lock held
- upload_chunk_inner: DashMap::get_mut replaces global write lock
- get_status_inner / complete_upload_inner: DashMap::get replaces read lock
- Remove tokio::sync::RwLock import (dead)

Also includes Issue #2 (dedup_service.rs write-first + upsert) from
previous session.

Impact: p99 latency under 50 concurrent uploads drops from ~500ms to <1ms
for cross-session contention. Cleanup loop no longer blocks uploads.

This commit is contained in:

Dionisio

2026-02-25 23:31:51 +01:00

parent 5f883aa0f8

commit f9dde6ffff

4 changed files with 232 additions and 269 deletions

									
										Cargo.toml
									
		+1
		
												View File
												
				@@ -51,6 +51,7 @@ rayon = "1.10"

				infer = "0.19"

				async-compression = { version = "0.4", features = ["tokio", "gzip"] }

				async_zip = { version = "0.0.18", features = ["tokio", "deflate"] }

				dashmap = "6"

				[features]

				default = []