In the previous recipe, we looked at how to analyze queries, how to decide what index needs to be created, and how we create indexes. This, by itself, is straightforward and looks reasonably simple. However, for large collections, things start getting worse as the index-creation time is large. There are some caveats that we need to keep in mind. The objective of this recipe is to throw some light on these concepts and avoid pitfalls while creating indexes, especially on large collections.
For the creation of indexes, we need to have a server up and running. A simple single node is what we will need. Refer to the Single node installation of MongoDB recipe in Chapter 1, Installing and Starting the MongoDB Server, for how to start the server.
Start connecting two shells to the server by just typing in mongo from the operating system shell. Both of them will, by default, connect to the test database.
Our test data for zipped codes...