What are the advantages of MongoDB over MySQL

The original title is “Is MongoDB the next big thing?”, please allow me to put big
thing is equivalent to MySQL, the most widely used open source database. As one of the most popular NoSQL at the moment, let’s take a look at its specific advantages and disadvantages.

Features of MongoDB

Simple query statement, no Join operation

Document-type storage, its data is stored in the binary Json format Bson. Its data is like Ruby hashes, or Python dictionaries, or PHP arrays

Sharding, MongoDB provides auto-sharding to achieve data scalability

GridFS, the file storage API provided by MongoDB

Array index, you can index an array property in the document

MapReduce, which can be used for complex statistics and parallel computing

High performance, by using mmap and timing fsync, frequent IO is avoided, making it more performant

Advantages of MongoDB

High performance, very fast (if you have enough RAM)

There is no fixed table structure, and there is no need for data migration to modify the table structure

The query language is simple and easy to use

Use Sharding to achieve horizontal expansion

Easy to deploy

When using MongoDB, you have to remember the following points:

MongoDB assumes you have large disk space

MongoDB assumes that your memory is also large enough to hold your hot data

MongoDB assumes that you are deployed on a 64-bit system (32-bit has a 2G limit, and the trial is okay)

MongoDB assumes your system is little-endian

MongoDB assumes you have multiple machines (doesn’t focus on single machine reliability)

MongoDB assumes you want to trade security for performance, while allowing you to trade performance for security

MongoDB is not very good at the following fields

Not very stable, especially auto-sharding still has many problems

Does not support SQL, which means that many of your tools that interface through SQL are no longer applicable

Persistence, MongoDB stand-alone reliability is not very good, downtime may lose data for a period of time

There are relatively few relevant documents, and new functions have this problem

It is difficult to find relevant talents, which is also one of the problems of the new function