How does having a long array of subdocuments in a field affect performance?

Question

{
  field_1: [
    {A: 1, ...}
    {A: 10, ...}
    {A: 2, ...}
  ]
}

What if field_1 has 10s of 1000s of subdocuments in its array?

What kind of query performance would be negatively affected? And why?

What if the subdocuments are multi key indexed?

Answer 1

If field_1 has a million subdocuments then it overload the stack in runtime and compiler will not be able to process that amount of data, it will result in crashing your code.