microsoft/qlib · error · QlibCacheException

It sees the key(lock:{repr(lock_name)[1:-1]}-wlock) of the r

Error message

It sees the key(lock:{repr(lock_name)[1:-1]}-wlock) of the redis lock has existed in your redis db now.
                    You can use the following command to clear your redis keys and rerun your commands:
                    $ redis-cli
                    > select {C.redis_task_db}
                    > del "lock:{repr(lock_name)[1:-1]}-wlock"
                    > quit
                    If the issue is not resolved, use "keys *" to find if multiple keys exist. If so, try using "flushall" to clear all the keys.
                

What it means

Error "It sees the key(lock:{repr(lock_name)[1:-1]}-wlock) of the redis lock has existed in your redis db now. You can use the following command to clear your redis keys and rerun your commands: $ redis-cli > select {C.redis_task_db} > del "lock:{repr(lock_name)[1:-1]}-wlock" > quit If the issue is not resolved, use "keys *" to find if multiple keys exist. If so, try using "flushall" to clear all the keys. " thrown in microsoft/qlib.

Source

Thrown at qlib/data/cache.py:245

            meta_path = cache_path.with_suffix(".meta")
            with meta_path.open("rb") as f:
                d = restricted_pickle_load(f)
            with meta_path.open("wb") as f:
                try:
                    d["meta"]["last_visit"] = str(time.time())
                    d["meta"]["visits"] = d["meta"]["visits"] + 1
                except KeyError as key_e:
                    raise KeyError("Unknown meta keyword") from key_e
                pickle.dump(d, f, protocol=C.dump_protocol_version)
        except Exception as e:
            get_module_logger("CacheUtils").warning(f"visit {cache_path} cache error: {e}")

    @staticmethod
    def acquire(lock, lock_name):
        try:
            lock.acquire()
        except redis_lock.AlreadyAcquired as lock_acquired:
            raise QlibCacheException(
                f"""It sees the key(lock:{repr(lock_name)[1:-1]}-wlock) of the redis lock has existed in your redis db now.
                    You can use the following command to clear your redis keys and rerun your commands:
                    $ redis-cli
                    > select {C.redis_task_db}
                    > del "lock:{repr(lock_name)[1:-1]}-wlock"
                    > quit
                    If the issue is not resolved, use "keys *" to find if multiple keys exist. If so, try using "flushall" to clear all the keys.
                """
            ) from lock_acquired

    @staticmethod
    @contextlib.contextmanager
    def reader_lock(redis_t, lock_name: str):
        current_cache_rlock = redis_lock.Lock(redis_t, f"{lock_name}-rlock")
        current_cache_wlock = redis_lock.Lock(redis_t, f"{lock_name}-wlock")
        lock_reader = f"{lock_name}-reader"
        # make sure only one reader is entering
        current_cache_rlock.acquire(timeout=60)

View on GitHub (pinned to 79633dd950)

Solutions

1. Clear the stale redis lock: run redis-cli, `select <redis_task_db>`, then `del "lock:<name>-wlock"`, and rerun your command.
2. If multiple stale keys exist, use `keys *` to inspect and `flushall` to clear all keys, then rerun.

When it happens

Trigger: This error is raised at qlib/data/cache.py:245 when the guard condition fails: "redis lock key already exists". It triggers when the code path receives input or a state that violates the precondition checked at this point — e.g. an unimplemented abstract method being called, an unsupported argument type/value, or an invalid configuration. To avoid it, satisfy the documented precondition before this call: implement the required method in your subclass, or pass a supported value of the expected type as described by the message.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/qlib@79633dd950 (2026-08-15). Data as JSON: /api/errors/61d661df4320ec5d. Report an issue: GitHub.