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How does the count function in MongoDB work?
Returns the count of documents that would match a find () query for the collection or view. The db.collection.count () method does not perform the find () operation but instead counts and returns the number of results that match a query.
What happens to the count in MongoDB after an unclean shutdown?
After an unclean shutdown of a mongod using the Wired Tiger storage engine, count statistics reported by count may be inaccurate. The amount of drift depends on the number of insert, update, or delete operations performed between the last checkpoint and the unclean shutdown.
Is there any way to recover recently deleted documents in MongoDB?
There is no rollback option (rollback has a different meaning in a MongoDB context), and strictly speaking there is no supported way to get these documents back – the precautions you can/should take are covered in the comments. With that said however, if you are running a replica set, even a single node replica set, then you have an oplog.
Is it possible to delete all data in MongoDB?
While I understand this is a bit old but I wanted to share something that I researched in this area that may be useful to others with a similar problem. The fact is that MongoDB does not Physically delete data immediately – it only marks it for deletion.
How to calculate limit and offset in MongoDB?
Bit of an odd one on query performance… I need to run a query which does a total count of documents, and can also return a result set that can be limited and offset. So, I have 57 documents in total, and the user wants 10 documents offset by 20.
How to use below aggregation in MongoDB 3.6?
Using $facet and $group you can find documents with $limit and can get total count. You can use below aggregation in mongodb 3.4 Even you can use $count aggregation which has been introduced in mongodb 3.6. You can use below aggregation in mongodb 3.6
What is the prototype of limit ( ) in MongoDB?
The limit () method has the following prototype form: The behavior of limit () is undefined for values less than -2 31 and greater than 2 31. You must specify a numeric value for limit (). A limit () value of 0 (i.e. .limit (0)) is equivalent to setting no limit.