使用 Python Cassandra 驱动程序写入时出现服务器错误

Question

code=1000 [Unavailable exception] message="Cannot achieve consistency level ONE" info={'required_replicas': 1, 'alive_replicas': 0, 'consistency': 'ONE'}
code=1100 [Coordinator node timed out waiting for replica nodes' responses] message="Operation timed out - received only 0 responses." info={'received_responses': 0, 'required_responses': 1, 'consistency': 'ONE'}
code=1200 [Coordinator node timed out waiting for replica nodes' responses] message="Operation timed out - received only 0 responses." info={'received_responses': 0, 'required_responses': 1, 'consistency': 'ONE'}

我正在通过 python cassandra-driver version 2.6

插入 Cassandra Cassandra 2.0.13（用于测试的单节点）

以下是我的键空间和table定义：

CREATE KEYSPACE test_keyspace WITH replication = {   'class': 'SimpleStrategy',   'replication_factor': '1' };


 CREATE TABLE test_table (
  key text PRIMARY KEY,
  column1 text,
  ...,
  column17 text
 ) WITH COMPACT STORAGE AND
  bloom_filter_fp_chance=0.010000 AND
  caching='KEYS_ONLY' AND
  comment='' AND
  dclocal_read_repair_chance=0.000000 AND
  gc_grace_seconds=864000 AND
  read_repair_chance=0.100000 AND
  replicate_on_write='true' AND
  populate_io_cache_on_flush='false' AND
  compaction={'class': 'SizeTieredCompactionStrategy'} AND
  compression={'sstable_compression': 'SnappyCompressor'};

我试过的：

1) 多处理（协议版本设置为 1）每个进程都有自己的 cluster、session（default_timeout 设置为 30.0）

def get_cassandra_session():
    """creates cluster and gets the session base on key space"""
    # be aware that session cannot be shared between threads/processes
    # or it will raise OperationTimedOut Exception
    if CLUSTER_HOST2:
        cluster = cassandra.cluster.Cluster([CLUSTER_HOST1, CLUSTER_HOST2])
    else:
        # if only one address is available, we have to use older protocol version
        cluster = cassandra.cluster.Cluster([CLUSTER_HOST1], protocol_version=1)

    session = cluster.connect(KEY_SPACE)
    session.default_timeout = 30.0
    return session

2)批量插入（协议版本设置为2，因为Cassandra上启用了BatchStatement2.X）

def batch_insert(session, batch_queue, batch):
    try:
        insert_user = session.prepare("INSERT INTO " + db.TABLE + " (" + db.COLUMN1 + "," + db.COLUMN2 + "," + db.COLUMN3 +
                                      "," + db.COLUMN4 + ") VALUES (?,?,?,?)")
        while batch_queue.qsize() > 0:
            '''batch queue size is 1000'''
            row_tuple = batch_queue.get()
            batch.add(insert_user, row_tuple)

        session.execute(batch)
    except Exception as e:
        logger.error("batch insert fail.... %s", e)

以上函数被调用：

 batch = BatchStatement(consistency_level=ConsistencyLevel.ONE)
 batch_insert(session, batch_queue, batch)

元组存储在 batch_queue.

3)同步执行 几天前我 post 另一个问题，cassandra 抱怨超时问题。我正在使用同步执行进行更新。

谁能帮忙，这是我的代码问题还是 python cassandra 驱动程序问题或 Cassandra 本身？

万分感谢！

Answer 1

如果您的问题是关于顶部的那些错误，那么这些是服务器端错误响应。

第一个说您联系的协调器不能满足 CL.ONE 的请求，它认为节点是活动的。如果所有副本都关闭（更有可能是复制因子较低），就会发生这种情况。

另外两个错误是超时，协调器在 configured in the cassandra.yaml.

时间内没有从 'live' 个节点得到响应

所有这些都表明您连接的集群不健康。这可能是因为它不堪重负（高 GC 暂停）或遇到网络问题。检查服务器日志以获取线索。

Answer 2

我收到以下错误，看起来非常相似：

cassandra.Unavailable: Error from server: code=1000 [Unavailable exception] message="Cannot achieve consistency level LOCAL_ONE" info={'consistency': 'LOCAL_ONE', 'alive_replicas': 0, 'required_replicas': 1}

当我在代码中添加一个 sleep(0.5) 时，它运行良好。我试图写得太多太快了...

使用 Python Cassandra 驱动程序写入时出现服务器错误

Server Errors While Writing With Python Cassandra Driver

cassandra

python-2.7

datastax