What is the use of Capped Collection in MongoDB ?

webmaster — Wed, 13 Apr 2022 09:51:53 +0000

Capped collections are fixed-size collections means when we create the collection, we must fix the maximum size of the collection (in bytes) and it can store the maximum number of documents.
After creation, it overwrites the existing documents, when we try to add more than documents to their capacity.
They are useful when we insert and retrieve documents based on insertion order, it supports high-throughput operations.
It is similar to circular buffers, which means once the fixed space is allocated for the capped collection.
Capped collection can also have _id field and by default, each _id field has an index.
In this collection, there are two parameters:

1. Name- It represents the name of the collection and it is of string type.
2. Options–It is an optional parameter.

Syntax:

This syntax specifies the following fields:

Collection Name: It is used to create as capped collection.
Capped: It is a Boolean field. If it is true, we create a capped collection.
auto indexed: It is a Boolean flag and use for auto-indexing. Indexes will be created automatically, if the flag is true.
Size: The maximum number of documents in bytes is represented by size. In context of capped collection, this is required field.
Max: The highest number of documents that permit the collection was represented by max.

how to remove a document from a capped collection in mongodb - Wikitechy