{ "XREAD": { "summary": "Return never seen elements in multiple streams, with IDs greater than the ones reported by the caller for each stream. Can block.", "complexity": "For each stream mentioned: O(N) with N being the number of elements being returned, it means that XREAD-ing with a fixed COUNT is O(1). Note that when the BLOCK option is used, XADD will pay O(M) time in order to serve the M clients blocked on the stream getting new data.", "group": "stream", "since": "5.0.0", "arity": -4, "function": "xreadCommand", "get_keys_function": "xreadGetKeys", "command_flags": [ "BLOCKING", "READONLY", "BLOCKING" ], "acl_categories": [ "STREAM" ], "key_specs": [ { "flags": [ "RO", "ACCESS" ], "begin_search": { "keyword": { "keyword": "STREAMS", "startfrom": 1 } }, "find_keys": { "range": { "lastkey": -1, "step": 1, "limit": 2 } } } ], "arguments": [ { "token": "COUNT", "name": "count", "type": "integer", "optional": true }, { "token": "BLOCK", "name": "milliseconds", "type": "integer", "optional": true }, { "name": "streams", "token": "STREAMS", "type": "block", "arguments": [ { "name": "key", "type": "key", "key_spec_index": 0, "multiple": true }, { "name": "ID", "type": "string", "multiple": true } ] } ] } }