Is it possible to query for a range of hashes of a hashed indexed key in mongodb?

问题

I have a hashed based sharding enabled for a key "userId" in a mongodb collection. Is it possible to get all documents whose hashed values of "userId" are between, let's say, "abcd" and "cdef"?

Thanks!

回答1:

One way that I found is to use the following query:

db.mycollection.find({
"$and": [
  {_id: {"$gt": -5012941854059245285}}, 
  {_id : {"$lt": -4712634714892678072}}
]}).hint({_id: "hashed"})

where the long numbers are hashed values of _id. It works for me, but is it the best way of doing so? Can I be sure that it will work with the upcoming releases of mongodb?

来源：https://stackoverflow.com/questions/17726236/is-it-possible-to-query-for-a-range-of-hashes-of-a-hashed-indexed-key-in-mongodb