How to check the document size of mongo db and increase limit

hello everyone
i have created a accounting management in meteor framework now its been 3 months i was working very fine but now it has become very slow i think it is because of data store in my mongo db. i read in mogodb docummentation that i has 16 mb documnet limit size. so i want to know how to check my documnet size and how to increase the limit

thanks in advance

You can check document sizes from the Meteor Mongo shell:

meteor mongo
> Object.bsonsize(db.yourcollection.findOne({_id:'someDocId'}))

The 16MB limit is a hard limit (excepting GridFS documents):

Poor performance is much more likely to be due to not having good indexes on your collections.

thank you for your valuable reply it took me 22 hours to figure out what did you say now i solved the problem by applying good indexes to my collections. one thing that i still did not understand is Grid FS Documnet you said . do i have to install it manually or there some code changes in my meteor application or is it applicable in meteor mongo