Undrained connection pool Debugging Lab

Undrained connection poolNetwork & ConnectivityHardPreparing workspaceAutosaved

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Incident Dossier

Undrained connection pool

After a busy hour, the worker is holding tens of thousands of sockets, the process is approaching its file-descriptor limit, and fresh connection attempts start timing out. The pool exposes a configurable `max` capacity that is never enforced on the way back in.

Initial failing signalPool size exceeds capacity after extra releasesExpected size stays at max=2 after three releases · received size grows to 3

Progress

1Reproduce the bugRun checks

2Edit the fixOpen

3Pass checksOpen

4Submit fixOpen

Reproduction Steps

Run npm test.
Inspect the failing assertion: three releases against a max=2 pool ended up with three idle connections.
Trace release in the pool and compare against the capacity contract.
Evict the oldest entry when the pool is already at capacity.

Focus Mode

Start

src/pool.js

Likely area

src/pool.js

Progressive hints

Hints reveal broad direction first, then narrow toward the suspect path without showing hidden tests or exact solution code.

TopicNetwork & Connectivity

DifficultyHard

Est. time22 min

Workspacecreating

Explorer

Preparing workspace files…

Evidence Map

Failing signal loaded from challenge API
Workspace files loaded from workspace API
Results rendered only after API run/submit

Autosaved

workspace

Outputread-onlyready$ workspace boot

Workspace booting...