{ "XLEN": { "summary": "Return the number of entries in a stream", "complexity": "O(1)", "group": "stream", "since": "5.0.0", "arity": 2, "function": "xlenCommand", "command_flags": [ "READONLY", "FAST" ], "acl_categories": [ "STREAM" ], "key_specs": [ { "flags": [ "RO" ], "begin_search": { "index": { "pos": 1 } }, "find_keys": { "range": { "lastkey": 0, "step": 1, "limit": 0 } } } ], "arguments": [ { "name": "key", "type": "key", "key_spec_index": 0 } ] } }