Question

In MongoDB using Linux how do you

Execute the command to find the size of a single document of your choosing from the enron database

Execute the command to find the size of the collection of documents in the enron database

Answer 1

1. In MongoDB for finding the size of a single document from database you have to execute following commands-

>bsonSize operator to get thedocument size.

-db.test.aggregate([

{

"$project":{

"name": abc,

"object_size":{ "$bsonSize": "$$ROOT"}

}

}

])

also

>Object.bsonSize(db,test.findOne({type:"auto"})) this instruction will gives you document size in bytes.

also for more information you can use following commands,

>dbStats.avgObjSize- this command will give you average size of documents in bytes. this is datasize divided by the number of documents.

2.Command to find the size of collection of documents,

>dbStats.objects- this command will give you a count of the number of objects i.e. documents in the database across all collections means size of collection of documents.

>db.runCommand( {<count>}) -to run a command against the current database,use following command to count number of documents

for more information you can use following command,

>db.collection.stats() - this function or command can help you to get all the information we need about the sizeof our collection using the stats() funtion on collection.