Creating an index

In this recipe, we will be using a fairly large dataset and add it into MongoDB. Then we will examine how a query executes in this dataset with and without an index.

Getting ready

Assuming that you are already running a MongoDB server, we will be importing a dataset of around 100,000 records available in the form of a CSV file called chapter_2_mock_data.csv. You can download this file from the Packt website.

1. Import the sample data to the MongoDB server:

$mongoimport --headerline --ignoreBlanks --type=csv -d mydb -c mockdata -h localhost chapter_2_mock_data.csv

You should see output like this:

2017-06-18T08:25:08.444+0530    connected to: localhost
2017-06-18T08:25:09.498+0530 imported 100000 documents

2. Connect to the MongoDB instance and open a mongo shell:

mongo localhost:27017

3. Check that the documents are in the right place:

use mydb
db.mockdata.count()

You should see the following result:

105000

4. Let's fetch a document with the explain() method:

> db.mockdata.find({city:'Singapore...