Question

我正在尝试使用扫描功能从数据库中的表中检索任何10个结果，如下所示：

  conn = boto.connect_dynamodb(
         aws_access_key_id=config.AWS_KEY,
         aws_secret_access_key=config.AWS_SECRET)

  table = conn.get_table('tablename')
  results = table.scan(attributes_to_get={'id'},
            max_results=10)

  for item in results:
    print item

  ./dbtest.py
   {'id': 'SkAJWDUZPSNrwepf7gdnFhExXPFABmqLjk1ADDRJuoo'}
   {'id': 'RjAVvd4SAmjtUbXEYmzBaIIDuruL5UZWEQPdcpj4XRc'}
   ...

但是最后我得到了这个错误（在返回正确的结果之后）：

Traceback (most recent call last):
  File "./mediatest.py", line 23, in <module>
    for item in results:
  File "/usr/lib/python2.7/dist-packages/boto/dynamodb/layer2.py", line 767, in scan
    object_hook=item_object_hook)
  File "/usr/lib/python2.7/dist-packages/boto/dynamodb/layer1.py", line 521, in scan
    return self.make_request('Scan', json_input, object_hook=object_hook)
  File "/usr/lib/python2.7/dist-packages/boto/dynamodb/layer1.py", line 121, in make_request
    retry_handler=self._retry_handler)
  File "/usr/lib/python2.7/dist-packages/boto/connection.py", line 746, in _mexe
    status = retry_handler(response, i, next_sleep)
  File "/usr/lib/python2.7/dist-packages/boto/dynamodb/layer1.py", line 148, in _retry_handler
    json_response)
boto.exception.DynamoDBResponseError: DynamoDBResponseError: 400 Bad Request
{'Message': 'Expected null', '__type': 'com.amazon.coral.service#SerializationException'}

我不处理需要处理的事情吗？

Answer 1

扫描线上有错误：

results = table.scan(attributes_to_get={'id'},
        max_results=10)

而不是

results = table.scan(attributes_to_get=['id'],
        max_results=10)

编辑：

这适用于Boto 2.5.2

import boto

db = boto.connect_dynamodb()

table = db.get_table('MyTable')
res = table.scan(attributes_to_get=['id'], max_results=10)

for i in res:
    print i

DynamoDB扫描函数返回正确的结果，但使用DynamoDBResponseError

1 个答案: