使用带有多个ndb.get_multi_async的yield

Question

我正在尝试从appengine数据存储区提高当前查询的效率.目前,我正在使用同步方法:

class Hospital(ndb.Model):
      name = ndb.StringProperty()
      buildings= ndb.KeyProperty(kind=Building,repeated=True)
class Building(ndb.Model):
      name = ndb.StringProperty()
      rooms= ndb.KeyProperty(kind=Room,repeated=True)
class Room(ndb.Model):
      name = ndb.StringProperty()
      beds = ndb.KeyProperty(kind=Bed,repeated=True)
class Bed(ndb.Model):
      name = ndb.StringProperty()
      .....

目前我经历了愚蠢的事情:

currhosp = ndb.Key(urlsafe=valid_hosp_key).get()
nbuilds = ndb.get_multi(currhosp.buildings)
for b in nbuilds:
   rms = ndb.get_multi(b.rooms)
   for r in rms:
      bds = ndb.get_multi(r.beds)
      for b in bds:
          do something with b object

我想使用get_multi_async将其转换为更快的查询

我的困难在于如何做到这一点？有任何想法吗？

最好的乔恩

Answer 1

使用上面给定的结构,有可能,并确认您可以使用一组tasklet解决此问题.这是一个重大在迭代方法加快.

@ndb.tasklet
def get_bed_info(bed_key):
    bed_info = {}
    bed = yield bed_key.get_async()
    format and store bed information into bed_info
    raise ndb.Return(bed_info)

@nbd.tasklet
def get_room_info(room_key):
    room_info = {}
    room = yield room_key.get_async()
    beds = yield map(get_bed_info,room.beds)
    store room info in room_info
    room_info["beds"] = beds
    raise ndb.Return(room_info)

@ndb.tasklet
def get_building_info(build_key):
    build_info = {}
    building = yield build_key.get_async()
    rooms = yield map(get_room_info,building.rooms)
    store building info in build_info
    build_info["rooms"] = rooms
    raise ndb.Return(build_info)

@ndb.toplevel
def get_hospital_buildings(hospital_object):
    buildings = yield map(get_building_info,hospital_object.buildings)
    raise ndb.Return(buildings)

现在来自医院功能的主要电话,你有医院对象(医院).

hosp_info = {}
buildings = get_hospital_buildings(hospital_obj)
store hospital info in hosp_info
hosp_info["buildings"] = buildings
return hosp_info

你去!它非常高效,并使计划在GAE主干内以最快的方式完成所有信息.