How to force MongoDB to use the BasicCursor instead of an index?

To force MongoDB to use a BasicCursor instead of an index, use the hint() method with $natural: 1. This bypasses any existing indexes and performs a collection scan in natural document order.

Syntax

db.collection.find(query).hint({ $natural: 1 });

Create Sample Data

First, let's create an index and insert some test documents ?

db.demo31.createIndex({"StudentFirstName": 1});

{
    "createdCollectionAutomatically": true,
    "numIndexesBefore": 1,
    "numIndexesAfter": 2,
    "ok": 1
}

db.demo31.insertMany([
    {"StudentFirstName": "John"},
    {"StudentFirstName": "Jace"},
    {"StudentFirstName": "Chris"},
    {"StudentFirstName": "James"}
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5e174f8fcfb11e5c34d898c1"),
        ObjectId("5e174f97cfb11e5c34d898c2"),
        ObjectId("5e174f9ccfb11e5c34d898c3"),
        ObjectId("5e174fa0cfb11e5c34d898c4")
    ]
}

Example: Force BasicCursor Usage

Query for students whose names start with "Ja" using BasicCursor instead of the index ?

db.demo31.find({"StudentFirstName": {$regex: '^Ja'}}).hint({ $natural: 1});

{ "_id": ObjectId("5e174f97cfb11e5c34d898c2"), "StudentFirstName": "Jace" }
{ "_id": ObjectId("5e174fa0cfb11e5c34d898c4"), "StudentFirstName": "James" }

Verify Collection Scan

Use explain() to confirm MongoDB is performing a collection scan ?

db.demo31.find({"StudentFirstName": {$regex: '^Ja'}}).hint({ $natural: 1}).explain("executionStats");

Key Points

• hint({ $natural: 1 }) forces a collection scan in insertion order
• Use $natural: -1 to scan in reverse insertion order
• BasicCursor is slower than indexes but useful for testing or specific scenarios

Conclusion

The hint({ $natural: 1 }) method forces MongoDB to use BasicCursor for collection scanning instead of available indexes. This bypasses index optimization and scans documents in their natural storage order.