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How to force MongoDB to use the BasicCursor instead of an index?
To avoid using index, use hint() in MongoDB. Let us create a collection with documents −
> db.demo31.createIndex({"StudentFirstName":1});
{
"createdCollectionAutomatically" : true,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
> db.demo31.insertOne({"StudentFirstName":"John"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e174f8fcfb11e5c34d898c1")
}
> db.demo31.insertOne({"StudentFirstName":"Jace"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e174f97cfb11e5c34d898c2")
}
> db.demo31.insertOne({"StudentFirstName":"Chris"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e174f9ccfb11e5c34d898c3")
}
> db.demo31.insertOne({"StudentFirstName":"James"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e174fa0cfb11e5c34d898c4")
}Display all documents from a collection with the help of find() method −
> db.demo31.find();
This will produce the following output −
{ "_id" : ObjectId("5e174f8fcfb11e5c34d898c1"), "StudentFirstName" : "John" }
{ "_id" : ObjectId("5e174f97cfb11e5c34d898c2"), "StudentFirstName" : "Jace" }
{ "_id" : ObjectId("5e174f9ccfb11e5c34d898c3"), "StudentFirstName" : "Chris" }
{ "_id" : ObjectId("5e174fa0cfb11e5c34d898c4"), "StudentFirstName" : "James" }Following is the query to force MongoDB to use BasicCursor instead of an index −
> db.demo31.find({"StudentFirstName": {$regex: '^Ja'}}).hint({ $natural: 1});This will produce the following output −
{ "_id" : ObjectId("5e174f97cfb11e5c34d898c2"), "StudentFirstName" : "Jace" }
{ "_id" : ObjectId("5e174fa0cfb11e5c34d898c4"), "StudentFirstName" : "James" }
Updated on: 02-Apr-2020
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