Poor lookup aggregation performance

Question

I have two collections

Posts:

{
    \"_Id\": \"1\",
    \"_PostTypeId\": \"1\",
    \"_AcceptedAnswerId\": \"192\",
    \"_CreationDate\": \"2012-02-         


        

Answer 1

First use $match then $lookup. $match filter the rows need to be examined to $lookup. It's efficient.