redis/redis-py · error · DataError

No key specified

Error message

No key specified

What it means

Raised by JSON.DEBUG (redis/commands/json/commands.py:830) as a DataError when subcommand is 'MEMORY' but no key argument is supplied. The MEMORY subcommand requires a key (and optional path) to measure, so the library rejects the call before sending JSON.DEBUG MEMORY with no target.

Solutions

1. Pass a non-None key: client.json().debug('MEMORY', 'mykey').
2. Optionally also pass a path: client.json().debug('MEMORY', 'mykey', '$.field').
3. For HELP no key is needed.

Example fix

# before
client.json().debug('MEMORY')
# after
client.json().debug('MEMORY', 'mykey')

def safe_json_debug_memory(key):
    if not key:
        raise ValueError('JSON.DEBUG MEMORY requires a key')
    return key

def has_debug_key(key) -> bool:
    return isinstance(key, str) and bool(key)

from redis.exceptions import DataError
try:
    client.json().debug('MEMORY', key)
except DataError as e:
    if 'No key' in str(e):
        raise  # caller must supply a key
    raise

When it happens

Trigger: Calling client.json().debug('MEMORY') or client.json().debug('MEMORY', None). The key parameter defaults to None and is only checked when subcommand == 'MEMORY'.

Common situations: Forgetting the key, reusing a debug('HELP') call signature for MEMORY, or a variable that resolved to None.

Related errors

• The only valid subcommands are
• Invalid FPHA type: . Must be one of
• nx and xx are mutually exclusive: use one, the other or…
• XRANGE count must be a positive integer
• XREAD block must be a non-negative integer

AI-assisted analysis of redis/redis-py@6a6b581b48 (2026-08-10). Data as JSON: /api/errors/16e1800381cebfe2. Report an issue: GitHub.

Appendix: source

Thrown at redis/commands/json/commands.py:830

    def debug(
        self,
        subcommand: str,
        key: str | None = None,
        path: str | None = Path.root_path(),
    ) -> (int | list[str]) | Awaitable[int | list[str]]:
        """Return the memory usage in bytes of a value under ``path`` from
        key ``name``.

        For more information see `JSON.DEBUG <https://redis.io/commands/json.debug>`_.
        """  # noqa
        valid_subcommands = ["MEMORY", "HELP"]
        if subcommand not in valid_subcommands:
            raise DataError("The only valid subcommands are ", str(valid_subcommands))
        pieces = [subcommand]
        if subcommand == "MEMORY":
            if key is None:
                raise DataError("No key specified")
            pieces.append(key)
            pieces.append(str(path))
        return self.execute_command("JSON.DEBUG", *pieces)

    @overload
    def jsonget(self: SyncClientProtocol, *args, **kwargs) -> JsonType | None: ...

    @overload
    def jsonget(
        self: AsyncClientProtocol, *args, **kwargs
    ) -> Awaitable[JsonType | None]: ...

    @deprecated_function(
        version="4.0.0", reason="redisjson-py supported this, call get directly."
    )
    def jsonget(self, *args, **kwargs) -> (JsonType | None) | Awaitable[
        JsonType | None
    ]:

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