pymongo - 执行并行查询

Question

这是我想要并行化的伪代码，但不知道从哪里开始

from pymongo import MongoClient
client = MongoClient('localhost', 27017)
db = client['myDB']
collection = db.myCollection

test_list = ['foo', 'bar']
result_list = list()

for el in test_list:
     result_list.append(collection.distinct('attrib',{'version': el}))

我知道如何用joblib创建并行循环，但我不知道如何并行查询MongoDB，我应该创建多个客户端或集合吗？如果我只是用joblib重写它而不关心MongoDB，上面的代码是否会起作用？

Answer 1

您可以在单独的线程中运行请求：

from multiprocessing.dummy import Pool as ThreadPool 

from pymongo import MongoClient


client = MongoClient('localhost', 27017)
db = client['myDB']
collection = db.myCollection

thread_pool_size = 4
pool = ThreadPool(thread_pool_size) 


def my_function(el):
    return collection.distinct('attrib', {'version': el}))


test_list = ['foo', 'bar']
result_list = pool.map(my_function, test_list)