Scheme rewriting of MongoDB configuration weights

I want to configure a weight pool, have 3 weights a,b,c, choose 2 IDs according to different weights

My original design was

Weight A:[id1,id2 ...]

Weight B:[id1,id2 ...]

Weight C:[id1,id2 ...]

The operations of the weights are $push, $pop, and take the entire table operation, so that if frequent operations are likely to cause the marked

One of my colleagues suggested another option:

{

{

Uid:id1

Weight:a

}

{

Uid:id2

Weight:b

}

......

}

Just add the weight key to the index and fetch all the a documents according to the weight index.

The following advantages are as follows:

Directly with $set can change the weight, (with Pop,push) pop a value will traverse the array, the data volume is large, inefficient, and even may lead to lock table.

Weight the index, the speed of the full ID of the a weight is 2/3 faster than the index (indexed, which is the direct lookup).

Scheme rewriting of MongoDB configuration weights