This article was written by Darshan Jayarama . MongoDB is a flexible schema database. This means you have the flexibility to modify the structure of the data store. One collection can have 5 fields in one row(document), 10 in another row, 1000 in another row, and 1 in another row. It doesn't matter how the structure has been aligned in the collection. If you are a developer with a SQL background, you may find this to be a fantasy, like a science fiction movie. However, that is the flexibility you can achieve with the help of MongoDB . A good percentage of people choose MongoDB for this flexible schema, but let it be known that abusing this feature could cost you big time. I would like to share some of the story from when I was working with customers to tune the application's performance. Massive boundless array Problem : One customer had ping data from an IOT device stored in an array field.…