Cross index field getting queried?

I have two separate indices A and B. Both indices have their own document structure.

One field name is common between documents of A and B i.e. userName.

When i query

POST /A/_search
{
"term": {
"userName": "james"
}
}

What is the possibility that this query will also check for the documents on index B ??
My expectation is, it should not go and check any document of index B.

No. It will query only A.

Thanks @dadoonet .
That will help me avoid querying a million docs :slight_smile: