Start from zero Redis cache

This article mainly introduces about starting from zero Redis cache, has a certain reference value, now share to everyone, have the need for friends can refer to

1. About Redis

Redisis an open source useANSIClanguageWrite, support network, log type that can be persisted based on memory,Key-valueDatabase, and is available in multiple languagesAPI. From .years3Month thefrom the day,Redisthe development work byVMwarehost. From -years5month begins,Redisthe development byPivotalsponsorship.

Redisis aKey-valueStorage System. and theMemcachedSimilarly, it supports the storage ofvaluetypes are relatively more, includingString (string),List (Linked list),Set (Collection),Zset (sorted set--ordered Collection)and theHash(hash type). TheseData Typeall supportPush/pop,Add/removeand take the intersection of the set and the difference set and richer operations, and these operations are atomic. On this basis,Redissupports sorting in a variety of different ways. With thememcached, the data is cached in memory in order to ensure efficiency. The difference isRedisperiodically writes the updated data to the disk or writes the modification to the appended record file, and on this basis implements theMaster-slave (Master)synchronization.

Redisis a high-performanceKey-valuedatabase. RedisTo a large extent compensatedmemcachedThis type ofKey/valueThe lack of storage, in the DepartmentSub-occasions can be a good complement to the relational database. It provides aJava,C + +,C #,PHP,JavaScript,Perl,object-c,Python,Ruby,Erlangand other clients, the use is very convenient. [1]

Redis supports master-slave synchronization. Data can be synchronized from the primary server to any number of slave servers, from the server to the primary server that is associated with other slave servers. This enables Redis to perform single-layer tree replication. You can write to the data intentionally or unintentionally. Because of the full implementation of the Publish / subscribe mechanism, you can subscribe to a channel and receive a complete message release record from the master server when the tree is synchronized anywhere from the database. Synchronization is helpful for the scalability and data redundancy of read operations.

Redis The official website address, very good remember, is Redis.io . (specifically checked, the domain name suffix io belongs to the national domain name, is British Indian Ocean Territory, namely British Indian Ocean Territory)

Currently, Vmware in funding the Redis development and maintenance of the project.

2. Installation of Redis

Unzip the installation file

After the decompression

Perform make to compile

Compile OK,

Enter SRC directory

REDIS-CLI Terminal operation

Redis-server starting a Redis service file

Redis-benchmark pressure test File

REDIS-CHECK-XX Inspection Vehicle backup File script

Create a Redis run directory and copy two running files past

Copy config file past

3. Start the Redis service

Front-end boot Redis service Success Flag

./redis-server

At this point, there is a problem, the current start is not closed, a close will be gone, so need to modify

Stop Service CTRL + Z

Stop the Redis service first

Use the background to start the Redis service

Vim redis.conf

Change to Yes to save, set background to start Redis

Start again

Discovery or front-end startup

Start with a configuration file to start with

View the next Redis process

Discover that Redis is up

4. Simple to use

Three variables are set, all three of which are stored in memory

How to read?

get!

5. Specific operation

1. Operation of Key

In Redis, out of the "\ n" and the space can not be the name of the composition of the content, the other content can be used as the name of the key part, the name length does not require

In other words, it's the variable name.

Code	Role
Exists Key	Whether there is
Del key1 Key2 ....	Deletes the specified key
Type Key	Returns the value type of the given key
Key pattern	Returns all keys that match the specified pattern
Rename Oldkey Newkey	Change the name
Dbsize	Returns the number of keys for the current database
Expire Key seconds	Specify an expiration time for key
Ttl Key	Returns the number of seconds expired for key
Select Db-index	Select Database
Move Key Db-index	Move key from the current database to the specified database
Flushdb	Delete all keys in the current database
Flushall	Remove all keys from all databases

Here are examples of the use of one

2. Operation of type String

String is the most basic type of Redis

A Redis string can contain any data, including JPG images or serialized objects

Maximum limit for a single value value is 1G bytes

Code	Role
Set Key value	Sets the value of the key corresponding to string type
Mset Key1 Value1...keyn Valuen	Set values for multiple keys at once
Mget key1 Key2 ... KeyN	Get the value of multiple keys at once
INCR Key	Do + + operations on the value of key
DECR key	Ibid.-Operation
Incrby Key Integer	Same INCR plus specified value
Decrby Key Integer	Same DECR minus specified value
Append Key value	Append value to the string of the specified key
Substr Key Start end	Returns the string value of the truncated key

3. Introduction and use of List linked list types

The list type is actually a doubly linked list

If you want to query the top 10 most recent users,

To check each other, too much consumption of resources

List Chain Representation example diagram:

Save the latest 5 user information from the login system via list lists

The new user comes in and the old user kicks out

How does the list work?

Code	Role
Lpush Key string	Adds a string element to the head of the list in key
Rpop Key	Deletes an element from the tail of the list and returns the element to delete
Lien Key Returns key	The length of the corresponding list, the key value does not exist return 0, if the key corresponding type is not a list return error
Rpush Key string	Ibid., add at tail
Lpop Key	Removes the element from the head of the list and returns the deleted element
Ltrim Key Start end	Intercept list, preserving elements within a specified range

4. Set Collection type

Redis's set is an unordered collection of type string.

The set element can contain a maximum of (2 of 32 square-1) elements

Individual elements in each collection cannot be duplicated

Code	Role
Sadd Key Member	Adds a string element to the set set of key corresponding to return success 1
Srem Key Member	Removed the given element from key corresponding set, successfully returned 1
Smove P1 P2 Member	Remove the member from the P1 corresponding set and add it to the P2 corresponding set
SCard Key	Returns the number of elements of a set
Sismember Key Member	Determine if member exists in set
Sinter key1 Key2 ....	Returns the intersection of all given keys
Sunion Key1 Key2	Returns the set of all the given keys
Sdiff Key1 Key2.	Returns the difference set for all given keys
Smembers Key	Returns the key corresponding to all the elements of the set, the result is unordered

There's a key five elements inside.

And then add a linken

5. Sortset Sort Collection type operations

Like set, sorted set is also a collection of string elements

The difference is that each element will be associated with a right

The elements in the collection can be obtained in an orderly manner by weight values

Case:

Get the hottest Top 5 posts learning with sort set implementation

Each element in the sorted collection is a value, a combination of weights

Code	Role
Zadd Key Score Member	Adds an element to the collection, the element exists in the collection, and updates the corresponding score
Zrem Key Member	Delete the specified element, 1 succeeded, 0 does not exist
Zincrby Key INCR Member	Increase the score value of the corresponding member according to the INCR amplitude and return the score value
Zrank Key Member	Returns the rank (subscript) of the specified element in the collection, where the element is an score from small to large
Zrange Key Start end	An element similar to the Irange operation from the specified interval in the collection, returning an ordered result
Zrevrange Key Start end	Ibid., return is in reverse order
Zcard Key	Returns the number of elements in the collection
Zscore Key Elemet	Returns the score corresponding to the given element
Zremrangebyrank Key min Max	Delete the element in the collection that is ranked in the given point range

6. Snapshot persistence

900 seconds a key change on (snapshot) Save

300 SEC 10 Key Change (snapshot) Save

10,000 key changes in a minute (snapshot) Save

The benefits of such control:

The frequency of data modification is very high, the frequency of backup is also high,

The frequency of data modification is low and the frequency of backup is low.

The name of the snapshot persistence save

Manually initiating snapshot persistence

If you are on this machine:

7. AoF Persistence

Essence: The user executes each "write" command (add, delete, modify) back to the file, restore the time to perform specific "write" instructions

Open AOF Persistence clears Redis internal data

Turn on aof persistence

Configuration file is modified restart service

View Redis process: Ps–a | grep Redis

-9 forced Kill process

Start a new process

AOF Append Persistent Backup frequency

Always force write to disk every time you receive a write instruction, it is slow, but it can maintain full persistence

Everysec is forced to write to disk once per second, a good compromise in performance and persistence, recommended

No full reliance on OS performance is best, persistence is not guaranteed

8. master-Slave mode

To reduce the load on each Redis server, you can set up a few and master-slave mode

A server payload "write"

Other server load "read"

The primary server is automatically synchronized to the slave server

Modify IP address and port number