Create capped collections

Source: Internet
Author: User

Capped collections: is a fixed-size collection.

It has high performance and queue expiration characteristics (expiration in order of insertion). Somewhat similar to the concept of "RRD".

The Capped collections is a high-performance automatic maintenance object Insertion Order. It is very suitable for similar logging functions and the standard collection differs, you must explicitly create a capped collection, specifying the size of a collection, in bytes. Collection data storage space values are allocated in advance. Note that the specified storage size contains the header information for the database.

If you create a normal collection:
> db.createcollection ("Mycollection01")

To create a capped collection:
> db.createcollection ("Mycoll", {capped:true, size:100000})

In capped collection, you can add new objects. Can be updated, however, objects do not increase storage space. If it increases, the update will fail. The database is not allowed to be deleted. Use the drop () method to delete all collection rows. Note: After deletion, you must explicitly recreate this collection. In a 32bit machine, the capped collection has a maximum storage of 1 billion bytes.

Create capped collections

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.