How do I get the size of a MongoDB database?

Probably the quickest and easiest way to check the size of a MongoDB collection is to use the db. collection. dataSize() method. This method returns the size of the collection in bytes.

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How do I check my DB stats in MongoDB?

The db. stats() method is used to return a document that reports on the state of the current database. The scale at which to deliver results. Unless specified, this command returns all data in bytes.

How does MongoDB calculate working set size?

If you are always accessing the last 12 month’s worth of data, then your working set is: 12GB (data) + 12GB (indexes) = 24GB. However, if you actually only access the last 3 month’s worth of data, then your working set is: 3GB (data) + 3GB (indexes) = 6GB.

What is the size of MongoDB?

The maximum BSON document size is 16 megabytes. The maximum document size helps ensure that a single document cannot use excessive amount of RAM or, during transmission, excessive amount of bandwidth. To store documents larger than the maximum size, MongoDB provides the GridFS API.

How do I find my collection size?

collection. totalSize() method is used to reports the total size of a collection, including the size of all documents and all indexes on a collection. Returns: The total size in bytes of the data in the collection plus the size of every index on the collection.

How does MongoDB calculate index size?

Learn commands in MongoDB get data size of database and storage size of database using db. stats(). MongoDB get index size and index storage size of a database using db.

How do I get metrics in MongoDB?

MongoDB Performance Monitoring Tools

mongostat Command. mongostat is used to get a quick overview of the status of your MongoDB server instance.
mongotop Command. mongotop tracks the amount of time a MongoDB instance spends reading and writing data per collection.
rs. status() Command.
db.
dbStats Command.
collStats Command.

How do you calculate collection size?

Given a Collection in Java, the task is to find the length or size of the collection. The Size of the different collections can be found with the size() method. This method returns the number of elements in this collection.

How much RAM do I need for MongoDB?

MongoDB requires approximately 1 GB of RAM per 100.000 assets. If the system has to start swapping memory to disk, this will have a severely negative impact on performance and should be avoided.

How does MongoDB use memory?

On MongoDB Atlas instances using the M40 tier or higher, 50% of the available memory is used for caching. The other 50% is used for in-memory operations and the other services running on the server. WiredTiger will try to fetch data from the cache, and then rely on disk storage.

How do I list collections in MongoDB?

To list all collections in Mongo shell, you can use the function getCollectionNames().

How do I count documents in MongoDB?

In MongoDB, the countDocuments() method counts the number of documents that matches to the selection criteria. It returns a numeric value that represents the total number of documents that match the selection criteria. It takes two arguments first one is the selection criteria and other is optional.

How does MongoDB choose index?

Generally, MongoDB only uses one index to fulfill most queries. However, each clause of an $or query may use a different index, and in addition, MongoDB can use an intersection of multiple indexes. The following documents introduce indexing strategies: Use the ESR (Equality, Sort, Range) Rule.

What is metrics in MongoDB?

Memory metrics

Metric Description	Name	Availability
Virtual memory usage (MB)	mem.virtual	serverStatus
Amount of memory used by the database process (MB)	mem.resident	serverStatus
Number of times MongoDB had to request from disk (per second)	extra_info.page_faults	serverStatus

How does MongoDB measure performance?

Is 1gb RAM enough for MongoDB?

Does MongoDB use a lot of memory?

And by default, MongoDB will reserve 50% of the available memory – 1 GB for the WiredTiger cache or 256 MB whichever is greater. For example, a system with 16 GB of RAM, would have a WiredTiger cache size of 7.5 GB. The size of this cache is important to ensure WiredTiger is performant.

Does MongoDB store data in RAM?

MongoDB is not an in-memory database. Although it can be configured to run that way. But it makes liberal use of cache, meaning data records kept memory for fast retrieval, as opposed to on disk.

How do I see all files in MongoDB?

Connect to a database using the getDatabase() method. Get the object of the collection from which you want to retrieve the documents, using the getCollection() method. Retrieve the iterable object containing all the documents of the current collection by invoking the find() method.

How do I list tables in MongoDB?

connect with the MongoDB database using mongo . This will start the connection. then run show dbs command. This will show you all exiting/available databases.
…
List all collections from the mongo shell:

db. getCollectionNames()
show collections.
show tables.

Is count faster than find MongoDB?

find({}). count() more fast then collection.

How do I count documents in a collection?

var value = db. collection. count(); and then print(value) or simply value , would give you the count of documents in the collection named collection .

Can MongoDB have multiple indexes?

MongoDB can use the intersection of multiple indexes to fulfill queries. In general, each index intersection involves two indexes; however, MongoDB can employ multiple/nested index intersections to resolve a query.

How many indexes can we create in MongoDB?

Maximum Ranges. A collection cannot have more than 64 indexes. The length of the index name cannot be longer than 125 characters. A compound index can have maximum 31 fields indexed.

How do I list a database in MongoDB?

In MongoDB, you can use the show dbs command to list all databases on a MongoDB server. This will show you the database name, as well as the size of the database in gigabytes. You can select any database using the use statement and work on it.