Find largest document size in MongoDB?

To find the largest document size in MongoDB, you need to write a script in the shell.

To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −

> db.largestDocumentDemo.insertOne({"StudentName":"John"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c8ed2e32f684a30fbdfd57d") } > db.largestDocumentDemo.insertOne({"StudentName":"Carol","StudentAge":22,"StudentCountryName":"US","TechnicalSubject":["C","C++","Java","MySQL"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c8ed3282f684a30fbdfd57e") } > db.largestDocumentDemo.insertOne({"StudentName":"Mike","StudentAge":22}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c8ed3382f684a30fbdfd57f") }

Display all documents from a collection with the help of find() method. The query is as follows −

> db.largestDocumentDemo.find().pretty();

The following is the output −

{ "_id" : ObjectId("5c8ed2e32f684a30fbdfd57d"), "StudentName" : "John" } {    "_id" : ObjectId("5c8ed3282f684a30fbdfd57e"),    "StudentName" : "Carol",    "StudentAge" : 22,    "StudentCountryName" : "US",    "TechnicalSubject" : [       "C",       "C++",       "Java",       "MySQL"    ] } {    "_id" : ObjectId("5c8ed3382f684a30fbdfd57f"),    "StudentName" : "Mike",    "StudentAge" : 22 }

Here is the query to find the largest document size in MongoDB −

> var largestDocumentSize = 0; > db.largestDocumentDemo.find().forEach(function(myObject) {    ... var currentDocumentSize = Object.bsonsize(myObject);    ... if(largestDocumentSize < currentDocumentSize ) {       ... largestDocumentSize = currentDocumentSize ;    ... } ... }); > print('The Largest Document Size =' + ' ' +largestDocumentSize);

The following is the output displaying the largest document size −

The Largest Document Size = 160