According to this answer,
The results are returned in the order they are found, which may coincide with insertion order (but isn't guaranteed to be)
I am concerned with order of documents in result. Doesnt matter how they are stored and indexed.
For example,
If I issue a query and I got result in order
[id1, id3, id6, id2]
Again I re-issued the same query then order may change or not?
It is fine if I get result like below,
[id1, idx, id6, id2] //Because I inserted idx and deleted id3
I expect id1 should always appear before id6, and id6 before id2. I am using mongodb in sharded environment.