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This article will explain in detail what Redis commands are commonly used, and the editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

Redis common command set

1) Connect operation command

Quit: close connection (connection)

Auth: simple password authentication

Help cmd: view cmd help, for example: help quit

2) persistence

Save: save data synchronization to disk

Bgsave: save data asynchronously to disk

Lastsave: returns the Unix timestamp of the last time data was successfully saved to disk

Shundown: save data synchronization to disk, and then shut down the service

3) remote service control

Info: provides server information and statistics

Monitor: real-time dump of received requests

Slaveof: change replication policy settings

Config: configuring the Redis server at run time

4) commands for value operations

Exists (key): confirm whether a key exists

Del (key): delete a key

Type (key): type of return value

Keys (pattern): returns all key that satisfy a given pattern

Randomkey: one of the randomly returned key spaces

Keyrename (oldname, newname): rename key

Dbsize: returns the number of key in the current database

Expire: set the active time of a key (s)

Ttl: get the active time of a key

Select (index): query by index

Move (key, dbindex): move the key in the current database to the dbindex database

Flushdb: deletes all key in the currently selected database

Flushall: delete all key in all databases

5) String

Set (key, value): assigns the value value to the string named key in the database

Get (key): returns the value of the string named key in the database

Getset (key, value): assign the last value to the string named key

Mget (key1, key2, … , key N): returns the value of multiple string in the library

Setnx (key, value): add string with the name key and the value value

Setex (key, time, value): add string to the library and set the expiration time time

Mset (key N, value N): set the values of multiple string in batch

Msetnx (key N, value N): if all string named key I do not exist

Incr (key): string add 1 operation named key

Incrby (key, integer): string named key adds integer

Decr (key): string minus 1 operation named key

Decrby (key, integer): string named key reduces integer

Append (key, value): the value of the string named key is appended to value

Substr (key, start, end): returns the substring of the value of string with the name key

6) List

Rpush (key, value): add an element with the value value to the end of the list named key

Lpush (key, value): add an element with a value of value to the list header named key

Llen (key): returns the length of the list named key

Lrange (key, start, end): returns the element between start and end in the list named key

Ltrim (key, start, end): intercept list named key

Lindex (key, index): returns the element of the index location in the list named key

Lset (key, index, value): assign a value to the element of index position in the list named key

Lrem (key, count, value): delete the element whose value is value in the list of count key

Lpop (key): returns and deletes the first element in the list named key

Rpop (key): returns and deletes the tail element in the list named key

Blpop (key1, key2, … Key N, timeout): the block version of the lpop command.

Brpop (key1, key2, … Key N, timeout): the block version of rpop.

Rpoplpush (srckey, dstkey): returns and deletes the trailing element of the list named srckey and adds it to the header of the list named dstkey

7) Set

Sadd (key, member): add the element member to the set named key

Srem (key, member): deletes the element member in the set named key

Spop (key): randomly returns and deletes an element in the set named key

Smove (srckey, dstkey, member): move to a collection element

Scard (key): returns the cardinality of the set named key

Sismember (key, member): whether member is an element of set named key

Sinter (key1, key2, … Key N): find the intersection

Sinterstore (dstkey, (keys)): find the intersection and save the intersection to the collection of dstkey

Sunion (key1, (keys)): Union set

Sunionstore (dstkey, (keys)): join and save the union to the collection of dstkey

Sdiff (key1, (keys)): subtraction set

Sdiffstore (dstkey, (keys)): take the difference set and save the difference set to the collection of dstkey

Smembers (key): returns all elements of a set named key

Srandmember (key): randomly returns an element of set with the name key

8) Hash

Hset (key, field, value): add the element field to the hash named key

Hget (key, field): returns the value corresponding to field in the hash named key

Hmget (key, (fields)): returns the value corresponding to field I in the hash named key

Hmset (key, (fields)): add the element field to the hash named key

Hincrby (key, field, integer): add integer to the value of field in the hash named key

Hexists (key, field): whether there is a domain with the key field in the hash named key

Hdel (key, field): delete the domain with the key field in the hash named key

Hlen (key): returns the number of elements in a hash named key

Hkeys (key): returns all keys in the hash with the name key

Hvals (key): returns the value of all keys in the hash named key

Hgetall (key): returns all keys (field) and their corresponding value in the hash named key

Redis advanced application

1. Security

After setting up the client connection, a password is required before any operation is specified. An external user can access 150W times in a second. The specific operation password modification setting the requirepass attribute in redis.conf gives the password. Of course, what I give here is primos.

After that, if you want to operate, you can log in and authorize it to use:

Sudo / opt/java/redis/bin/redis-cli-a primos

Or after entering the auth primos, you can operate at will.

2. Master-slave replication

When I did this, I prepared two virtual machines. The ip are 192.168.15.128 and 192.168.15.133 respectively.

Master-slave replication allows multiple slave server to have the same database replica as master server

The specific configuration is to configure slave on slave.

Slaveof 192.168.15.128 6379

Masterauth primos

If there is no master-slave synchronization, then check to see if it is a firewall problem. I use ufw. Just set up sudo ufw allow 6379.

At this time, you can check the specific situation through info.

3. Transaction processing

Redis's support for transactions is relatively simple. Redis can only ensure that commands in a transaction initiated by client can be executed continuously without inserting commands from other client. When a client issues a multi command in a connection, the connection enters the context of a transaction, and the subsequent command of the connection is not executed immediately, but is first placed in a queue. When the exec command is executed, redis executes all the commands in the queue sequentially.

For example, I have an example below.

Set age 100

Multi

Set age 10

Set age 20

Exec

Get age-- this content should be 20.

Multi

Set age 20

Set age 10

Exec

Get age-the content at this time becomes 10, which fully reflects the way it is executed in queue order.

Discard cancels all transactions, that is, transaction rollback

However, when there are individual errors in the execution of the redis transaction, the transaction will not be rolled back, the content that is not wrong will be executed, and the content of the error will be abandoned directly. At present, the latest 2.6.7 also has this problem.

Optimistic lock

Watch key if there is no change in watch's key, then outdate's transaction cannot be executed.

4. Persistence mechanism

Redis is an in-memory database that supports persistence

Snapshotting snapshot mode, the default storage method, which is written to the binary file of dump.rdb by default. You can configure redis to take snapshots automatically if more than m key are modified in n seconds.

In append-only file aof mode, when using aof, redis appends each function to the file, and when redis restarts, it reexecutes the saved life in the file.

Make it in memory.

5. Publish and subscribe message sbusribe publish operation, which is actually similar to the message publishing under linux.

6. Use of virtual memory

Can configure vm function, save path, maximum memory online, number of pages, page size, maximum worker thread

Temporarily modify the ip address ifconfig eth0 192.168.15.129

Redis-cli parameter

Usage: redis-cli [OPTIONS] [cmd [arg [arg...]

-h Server hostname (default: 127.0.0.1)

-p Server port (default: 6379)

-s Server socket (overrides hostname and port)

-a Password to use when connecting to the server

-r Execute specified command N times

-I When-r is used, waits seconds per command.

It is possible to specify sub-second times like-I 0.1

-n Database number

-x Read last argument from STDIN

-d Multi-bulk delimiter in for raw formatting (default:\ n)

C Enable cluster mode (follow-ASK and-MOVED redirections)

-- raw Use raw formatting for replies (default when STDOUT is not a tty)

-- latency Enter a special mode continuously sampling latency

-- slave Simulate a slave showing commands received from the master

-- pipe Transfer raw Redis protocol from stdin to server

-- bigkeys Sample Redis keys looking for bigkeys

-- eval Send an EVAL command using the Lua script at

-- help Output this help and exit

-- version Output version and exit

Examples:

Cat / etc/passwd | redis-cli-x set mypasswd

Redis-cli get mypasswd

Redis-cli-r 100 lpush mylist x

Redis-cli-r 100-I 1 info | grep used_memory_human:

Redis-cli-- eval myscript.lua key1 key2, arg1 arg2 arg3

(Note: when using-- eval the comma separates KEYS [] from ARGV [] items)

Common commands:

1) check the number of keys

Keys * / / View all keys

Keys prefix_* / / View all keys prefixed with "prefix_"

2) clear the database

Flushdb / / clear all keys of the current database

Flushall / / clear all keys for all databases

This is the end of this article on "what are the common commands in Redis?". I hope the above content can be helpful to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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