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Graph/event-loop-blocking-deadlock

AntiPattern

Event Loop Blocked

event-loop-blocking-deadlock

Synchronous locking or blocking calls (thread-wide locks, multi-lock ordering, sleep that releases/reacquires GIL, or command waits) stall the event loop or propagate aborting exceptions, leading to deadlocks, stalled progress callbacks, or downloads that never finish.

Node Details

Public graph metadata

Updated6/28/2026

Connections

30 linked nodes

MATCHESSolution

As long as you lock more than a single thing at a time, you risk deadlocks. — lock more than a single thing at a time. Tension: You hold B waiting for A, they hold A waiting for B. Outcome: one of you has to abort or you're stuck.

MATCHESSolution

I suggests you use rapyer, Which takes special care to handle deadlock problems. — Since you are using json models. Tension: deadlock problems.

MATCHESSolution

single worker running async loop. Outcome: So you have a single worker running async loop and you block that loop.

MATCHESSolution

Changed calling it to `await to_thread(CatalogHandler.catalog_check, user.group_name, req.source, req.csv)` — when this process is running. Tension: It makes function run in a separate thread without blocking main event loop. Outcome: everything seems to work.

MATCHESSolution

Using `asyncio.sleep()` in a loop is perfectly fine. Tension: every time you `await` the sleep, you effectively yield control back to the event loop. Outcome: calling `asyncio.sleep(0)` does not sleep at all, but only yields control back to the event loop.

MATCHESSolution

the reason for the various threads appearing in the logs — when you pass a synchronous generator to `EventSourceResponse`. Tension: a normal `def` function instead of `async def`. Outcome: please take a look at the implementation of the `EventSourceResponse` class.

MATCHESSolution

Ensure the server yields to the asyncio event loop while processing (e.g., add an `await asyncio.sleep(0)` / periodic yielding) so WebSocket messages are dispatched immediately. Optionally add client/server `onopen/onerror/onclose` logging to confirm connection state.

MATCHESSolution

any time you have an I/O bound process with lots of idle time — waiting for user input, waiting for a TLS handshake. Tension: wrapping it in an async task can let other code run.

MATCHESSolution

The issue was with keychain access. — the macos job keeps on hanging. Tension: I also had some trouble getting code signing and notarization to work. Outcome: creating a temporary one and unlocking it.

MATCHESSolution

removing the lock file, solved it immediately — the error was "simply" due to a freezing during the git commit. Tension: gpg: signing failed: Operation timed out. Outcome: what worked was this: https://gist.github.com/bahadiraraz/f2fb15b07e0fce92d8d5a86ab33469f7.

MATCHESSolution

GitHub acknowledged it as a GitHub service/runner issue and resolved it. After the service-side fix, queued jobs stopped getting stuck.

MATCHESSolution

If you raise an exception in it, it will propagate and abort the download — download progress callback. Tension: You can use try-catch to determine if the download was aborted or failed for other reasons. Outcome: raise an exception in it.

MATCHESSolution

Ensure the S3 download runs in a way that doesn’t block the event loop (i.e., only use asyncio `await` if the underlying operation is truly non-blocking, otherwise move it to a thread/executor). Use `asyncio.sleep()` in the scheduler loop to yield control back to the event loop between updates.

MATCHESSolution

bound it with a "progress ceiling" — a process emitting bytes but making NO semantic progress. Tension: a process emitting bytes but making NO semantic progress (livelock) would be shielded forever. Outcome: re-arms recovery after a long no-progress window even while bytes flow.

MATCHESSolution

Thread a second, lower-level liveness signal into the classifier — the timestamp of the last raw stdout byte from the child. Tension: Dead socket = no bytes = livenessAge grows = still aborts (correct). Alive-but-quiet = bytes flowing = livenessAge fresh = NOT aborted.

MATCHESSolution

Do not use `Thread.stop()`. Tension: you need to really validate your assumptions of what is possible in your complicated code base.

MATCHESSolution

Avoid running multiple DB operations concurrently on the same session by removing asyncio.gather and iterating sequentially, and/or use an async_scoped_session so each task uses its own session.

MATCHESSolution

Cause of the deadlock.

MATCHESSolution

Use virtual threads for blocking DB/IO work to improve scalability under the same small pool, or switch to a reactive database driver/event-loop model to avoid blocking carrier threads; adjust concurrency/throttling accordingly (semaphore/backpressure) rather than assuming the current JDBC + thread pool design remains optimal.

MATCHESSolution

Your code doesn't use any shared state (or even objects) between the different threads — running this code in a multithreaded environment. Tension: The only thing that may looks marignally relevant is calling the static `OPCPackage.open` method. Outcome: there shouldn't be any problem running this code in a multithreaded environment.

MATCHESSolution

Use asynchronous sending with callbacks. — If you're using KafkaTemplate.send() without handling the ListenableFuture returned. Tension: you're effectively blocking the calling thread until the message is acknowledged by the Kafka broker. Outcome: The addCallback method allows you to execute code when the send operation succeeds or fails, without blocking the main thread.

MATCHESSolution

I am seeing an increase in latencies in requests that do succeed — I have a logic of the sort :. Tension: none of them enforce a timeout on the total duration of the request. Outcome: Then properly close the connection in a finally / try-resource block.

MATCHESSolution

Use synchronization primitives, locks, or other publication mechanisms that establish a happens-before between the write and subsequent read

MATCHESSolution

Mysql driver 9.0.0+ (currently 9.1.0) has ReentrantLock(s) now — IF they were not hooked on mysql internal synchronized blocks. Tension: it should have helped. Outcome: and it should work as this enabled the virtual thread to go do something else.

MATCHESSolution

I can see that this isn't actually causing the thread in `myMethod` to interrupt — Thread.sleep(400);. Outcome: thread.start(); thread.interrupt(); thread.join(); assertNotNull(reference.get());.

MATCHESSolution

Tension: it was being looped infinitely, crashed and restarted every time. Outcome: fixes the issue.

MATCHESSolution

Fixed 30s retry on 429 keeps hammering. — when clearly rate-limited. Tension: keeps hammering. Outcome: Exponential backoff + hard rejection during cooldown.

MATCHESSolution

the goroutine blocks forever on the channel send because nobody is reading — When the parent context is cancelled, the goroutine blocks forever on the channel send because nobody is reading. Tension: if the result is ready at the exact moment the context cancels, which case fires?

MATCHESSolution

Stopped the active runner — background extraction does not consume Gemini quota. Tension: continuing futile retries. Outcome: waits until the Pacific reset instead of continuing futile retries.

MATCHESSolution

Rebuilt App.tsx as the OracleController beat machine. Outcome: running the authored cascade arrest→anchor→recognition→locked on setTimeout timers.

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