412在云数据存储中执行查询时没有找到匹配的索引。

Question

我正在使用gcloud-python库从云数据存储查询数据。把我的片段想象成这样

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

对于上面我得到的片段

    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Index.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？请帮帮我。

Answer 1

使用祖先的所有索引:是的，所以祖先键应该添加到查询中。没有祖先，您的索引配置需要另一个带有“祖先:否”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

索引配置文档表示索引配置应该在一个名为datastore-indexes.xml的XML文件中。