Redis basics: 2. Introduction to redis

Getting started overview

1. What is it?

Redis: Remote Dictionary Server (remote dictionary server). It is completely open source and free, written in C language, a high-performance KV distributed memory database that complies with the BSD protocol, and a NoSql database that runs on memory and supports persistence. Is currently one of the most popular NoSql databases.

Features:

  • Redis supports data persistence. The data in the memory can be stored on the disk, and it can be loaded again for use when restarting.
  • Redis not only supports simple KV type data, but also provides storage for list, set, zset, hash and other data structures
  • Redis supports data backup, that is, data backup in master-salve mode

2. What can you do

  • Memory storage and persistence: Redis supports asynchronous writing of data in memory to the hard disk without affecting the continued service.
  • The operation of fetching the latest N data, such as: you can put the IDs of the latest 10 comments in the redis list collection.
  • The simulation is similar to HTTPSession, which requires setting the expiration time.
  • Publish and subscribe message system
  • Timer, counter

3. Where to go

installation steps:

Download redis-3.0.4.tar.gz to the /opt directory of the server

After decompression, a folder appears: redis-3.0.4

Execute the make command in the redis-3.0.4 directory (you can use it to gcc -vcheck whether gcc is installed, if not, use yum to install it)

If you report this error:

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make distcleanlatermake

make install

Redis related commands are stored in /usr/local/bin

Modify redis.conf under /opt/redis-3.0.4/ (remember to backup), and set the daemon to yes

Start command:redis-server /opt/redis-3.0.4/redis.conf

Then use the client to enter:redis-cli -p 6379

Exit the client: enter exit in the client; exit redis: enter shutdown in the client

Miscellaneous basic knowledge after startup

The redis commands are as follows:

redis-benchmark can be used to measure performance~~

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  • There are 16 databases by default, which can be modified in the redis.conf file. Use in the client select [n]to switch databases (the index of the first database is 0)
  • dbsize: View the number of keys in the current database. keys *View what keys the current database has
  • flushdb: Clear the current library. flushallEmpty all libraries
  • Unified password management, all 16 libraries have the same password, either all are ok, or none of them can be connected
  • Redis indexes start from 0
  • Why is the default port 6379? Merz, Italian female singer