PyMongo事务错误:仅在副本集成员或mongos上允许事务编号

Question

当我使用pymongo 3.7事务功能连接到mongo服务器4.0时,出现此错误"只允许在副本集成员或mongos上使用交易号",我找不到任何解决此问题的答案.我的代码是:

from pymongo import MongoClient
conn = MongoClient(host, port)
tb = conn.collector_gateway.try_table
with conn.start_session() as session:
    with session.start_transaction():
        tb.insert_one({"sku": "abc123", "qty": 100}, session=session)

错误是:

Traceback (most recent call last):
  File "/Users/yuzgu/PycharmProjects/seller_loss_alert/try_mongo.py", line 22, in <module>
    tb.insert_one({"sku": "abc123", "qty": 100}, session=session)
  File "/Users/yuzgu/anaconda3/lib/python3.6/site-packages/pymongo/collection.py", line 693, in insert_one
    session=session),
  File "/Users/yuzgu/anaconda3/lib/python3.6/site-packages/pymongo/collection.py", line 607, in _insert
    bypass_doc_val, session)
  File "/Users/yuzgu/anaconda3/lib/python3.6/site-packages/pymongo/collection.py", line 595, in _insert_one
    acknowledged, _insert_command, session)
  File "/Users/yuzgu/anaconda3/lib/python3.6/site-packages/pymongo/mongo_client.py", line 1243, in _retryable_write
    return self._retry_with_session(retryable, func, s, None)
  File "/Users/yuzgu/anaconda3/lib/python3.6/site-packages/pymongo/mongo_client.py", line 1196, in _retry_with_session
    return func(session, sock_info, retryable)
  File "/Users/yuzgu/anaconda3/lib/python3.6/site-packages/pymongo/collection.py", line 590, in _insert_command
    retryable_write=retryable_write)
  File "/Users/yuzgu/anaconda3/lib/python3.6/site-packages/pymongo/pool.py", line 579, in command
    unacknowledged=unacknowledged)
  File "/Users/yuzgu/anaconda3/lib/python3.6/site-packages/pymongo/network.py", line 150, in command
    parse_write_concern_error=parse_write_concern_error)
  File "/Users/yuzgu/anaconda3/lib/python3.6/site-packages/pymongo/helpers.py", line 155, in _check_command_response
    raise OperationFailure(msg % errmsg, code, response)
pymongo.errors.OperationFailure: Transaction numbers are only allowed on a replica set member or mongos

由于mongo交易功能已于今年发布,我找不到解决方案,任何人都可以帮我解决这个问题吗？

Answer 1

事务仅在副本集设置（https://docs.mongodb.com/master/core/transactions/#transactions-and-replica-sets）中可用：

多文档事务仅适用于副本集。

当您尝试在独立mongod实例上执行事务操作时，将显示此错误消息。

请参阅“ 交易”页面以了解更多详细信息和要求。