在云数据存储中执行查询时没有找到匹配的索引

Question

我使用gcloud-python库从云数据存储查询数据。把我的代码片段想象成这样

from google.appengine.ext import ndb
from datetime import datetime
class Order(ndb.Model):
     order_name = ndb.StringProperty(required=True)
     date_created = ndb.DateTimeProperty(default= datetime.now())
#code for querying the cloud datastore
from gcloud.datastore.query import Query
date_start = datetime.combine(date(year=2015, month=08, day=01), time())
date_end = datetime.combine(date(year=2015, month=08, day=03), time())
query = Query(kind='Order')
query.add_filter('order_name', '=', 'grand-line-order')
query.add_filter('date_created', '<', date_end)
query.add_filter('date_created', '>', date_start)
iterator = query.fetch(limit=10)
records, more, cursor = iterator.next_page()
print records

对于上面的代码片段，我得到

    File "/Users/sathyanarrayanan/Desktop/app/services/cdr_helper.py", line 528, in fetch_cdr
    records, more, cursor = iterator.next_page()
  File "/Users/sathyanarrayanan/Desktop/app/gcloud/datastore/query.py", line 388, in next_page
    transaction_id=transaction and transaction.id,
  File "/Users/sathyanarrayanan/Desktop/app/gcloud/datastore/connection.py", line 257, in run_query
    datastore_pb.RunQueryResponse)
  File "/Users/sathyanarrayanan/Desktop/app/gcloud/datastore/connection.py", line 108, in _rpc
    data=request_pb.SerializeToString())
  File "/Users/sathyanarrayanan/Desktop/app/gcloud/datastore/connection.py", line 85, in _request
    raise make_exception(headers, content, use_json=False)
PreconditionFailed: 412 no matching index found.

我的指数。Yaml文件是这样的

indexes:
- kind: Order
  ancestor: yes
  properties:
  - name: date_created
- kind: Order
  ancestor: yes
  properties:
  - name: date_created
    direction: desc
- kind: Order
  ancestor: yes
  properties:
  - name: order_name
    direction: asc
  - name: date_created
    direction: desc
- kind: Order
  ancestor: yes
  properties:
  - name: order_name
    direction: asc
  - name: date_created
    direction: asc

我做错了什么吗?

Answer 1

所有的索引都使用ancestor:yes，所以应该在查询中添加祖先键。如果没有祖先，您的索引配置需要另一个带有'ancestor:no'的索引

- kind: Order
  ancestor: no
  properties:
    - name: order_name
      direction: asc
    - name: date_created
      direction: desc

注意:每个查询的特定索引

Answer 2

索引配置文档指出索引配置应该在一个名为datastore-indexes.xml的XML文件中