1. Introduction to redis
Nosql non-relational database key => value key-value pair
Redis is the abbreviation of Remote Dictionary Server (remote data service)
A memory cache database developed by Italian antirez (Salvatore Sanfilippo). The software is written in C language, and its data model is key-value
It supports rich data structures, such as “”String list (doubly linked list) hash (hash) set (set) sorted set (zset ordered set) big
Persistence (save data to disk), ensuring data security
Business usage scenarios:
①[Sort set] ranking application, take top n operations, such as sina Weibo hot topics
②[List] Obtain the latest N data or the latest data of a certain category
③[string] counter application
④[Set]Jsns(social network site) get mutual friends
⑤[Set] Anti-attack system (ip judgment) black and white list, etc.
Compared with memcached
①Redis not only supports simple k/v type data, but also provides storage of data structures such as list, set, zset, and hash. ②Redis supports master-slave (master-slave) mode applications.
③Redis supports data persistence, which can save the data in the memory to the disk, and can be loaded again for use when restarting. ④The maximum limit of Redis single value storage string is 512MB, and memcached can only save 1MB of data
⑤redis is single-core, memcached is multi-core
Since redis can only use a single core, and memcached can use multiple cores, in comparison, on average, redis on each core has higher performance than memcached when storing small data. However, in the data above 100K, the performance of memcached is higher than that of redis. Although redis has recently optimized the performance of storing large data, it is still a bit inferior to memcached. The conclusion is that no matter which one you use, the number of requests per second should not be the bottleneck.
You need to keep an eye on memory usage. For simple data storage like key-vlaue, the memory usage of memcached is higher. If the hash structure is used, the memory usage of redis will be higher. Of course, this all depends on the specific application scenario.
2. Redis source code compilation and installation and client test start
Official website: https://redis.io/
github: https://github.com/antirez/redis
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Source code compilation and installation
① Upload the software to the directory
redis-4.3.0.tgz php extension server01 and server03 installation
redis-5.0.5.tar.gz redis software server08 installation
② Unzip, compile and install
tar xvf redis-5.0.5.tar.gz cd redis-5.8.5 make PREFIX=/usr/local/redis install //This configuration directory
Use the file /usr/local/redis/bin
redis-cli command line client
redis-server server
③Test start
cd /usr/local/redis/bin
./redis-server //Start the server
2. Background startup configuration
① Copy the configuration file to the software directory
②Modify and edit the configuration file
vim /usr/local/redis/bin/redis.conf
/daemonize daemon process
③Start redis-server and add redis.conf parameters
cd /usr/local/redis/bin ./redis ./redis-server //Start redis background service
3. The command line client is simple to use
redis-cli -h
Client Help Parameters
3. Data structure type operation
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key
Keys containing spaces and newlines like “my key” and “mykey\
” are not allowed.
Key should not be too long. It takes up memory and the query is slow.
Key should not be too short.
Like u:1000:pwd:123456 is not as readable as user:1000:password:123456
2, String
string is the most basic type of redis
The string of redis can contain any data. The maximum limit of a single value of a jpg image base64 or serialized object is 512MB
If only string type is used, redis can be regarded as memcached with persistence feature
In a real business environment, it is only necessary to obtain whether the key has data and whether the key exists
3, List
key value(value1,value2,value3)
The list type is actually a doubly linked list. Add and delete elements from the head or tail of the linked list through push and pop operations, which makes the list can be used as a stack or a queue
In and out at the same end First in last out Stack Candied haws, the one inserted first can be eaten last
– end other – end out first in first out queue queue, first come first served
Header (left left)
Tail (right right)
Requirement: Display the last logged-in users
Design implementation:
①Log in a user, store the user name or id in the list
②Save from the head (left part), take from the head (left part)
User: xiaoming
xiaohua
xiaobaitu
rpop deletes the first element on the right of the list, and returns the column of the first logged-in user
xiaobaitu xiaohua xiaoming
lpop deletes the first element on the left of the list, and returns the stack of the last logged-in user
xiaobaitu xiaohua xiaoming
4, set
The set of redis is an unordered collection of string type. Duplicate elements are not allowed in the set
The set element can contain a maximum of (2 to the 32nd power-1) elements.
Regarding the set collection type, in addition to the basic addition and deletion operations, other commonly used operations include collection union, intersection, and difference. Through these operations, the friend recommendation function in sns can be easily implemented.
Tip: mysql connected table Venn diagram
https://www.cnblogs.com/sunjie9606/p/4167190.html
Requirements: Realize the storage of the circle of friends and the calculation of common friends
design:
key value
xiaomingFR xiaohong xiaoqiang xiaogang xiaohei xiaobai
xiaohongFR xiaoming xiaolv xiaolan xiaobai xiaohei
l set type operation
Add a string element to the set corresponding to the key, return 1 if successful, return 0 if the set element is already in the set,
The set corresponding to the key does not exist and returns an error
srem key member [menber]
Remove the given element from the set corresponding to the key, and return 1 on success
move p1 p2 menber
Remove the menber from the set corresponding to p1 and add it to the set corresponding to p
card key
Returns the number of elements in the set
sismenber key menber
Determine whether the menber is in the set
sinter key1 key2- –keyN
Returns the intersection of all given keys
sunion key1 key2 —.kegH
Returns the union of all given keys
sdiff keg1 key2—keyN
Returns the difference of all given keys
smenbers key
Returns all elements corresponding to the key in unordered order
5, zset
zadd key score menber
Add an element to the collection, update the corresponding score if the element exists in the collection
zren keg menber
Delete the specified element, 1 means success, if the element does not exist, return 0
zincrby key incr menber
Increase the score value of the corresponding menber according to the incr amplitude (positive or negative) and return the score value
zrank key menber
Returns the rank (subscript) of the specified element in the collection, the elements in the collection are sorted by score from small to large
zrevrank key nenber
As above, the elements in the collection are sorted by score from largest to largest
zrange key start end
Similar to the lrange operation, the elements of the specified range are removed from the collection. Returns ordered results
zrev range key start end
Same as above, the returned results are in reverse order of score
zcard key
Returns the number of elements in the collection
zscore key element
return score
zrenrangebyrank key min max
Deletes elements in the given range from the collection
6, Hash
Using redis as a cache, you can use a hash structure, which is more efficient in compression and use. Compared with string Hash to store data and relational database (mysql), the structure of a piece of stored data is very similar Key: value (field: value)
hash type
hset key field value
Set the hash field to the specified value, if the key does not exist, create it first
hget key field
Get the specified hash fieid
hmget key filed1—FieldN
Get all the specified hash filed
hnset key filed1 value1 —
filedN valueN
Set multiple fields of hash at the same time
hincrby key field integer
Add the specified hash filed to the given value
hexists key field
Test whether the specified fie1d exists
hdel key field
Delete the specified hash field
hlen key
Returns the number of fields of the specified hash
hkeys key
Return all fields of hash
hvals key
Return all values with the same hash
hgetall key
Return all filed and value of hash
devops: (username: devops, phone: 15313131313, email: 123456@qq.com)
Hash data type: storage and value are all through key, and the data stored in relational data string has nothing to do with it, it is independent
17301296261: (username: 17301296261, phone: 17301296261, email: devops@qq.com)
Fourth, data persistence operation
Data persistence (data is not lost after service or software restart)
If the data only exists in the memory, it will definitely be lost. To achieve persistence, the data needs to be stored in the disk (hdd ssd)
1, snapshotting (snapshot)
snap to take pictures in advance
By default snapshotting is enabled and there is a backup frequency
By looking at the configuration file you can see
set num1 1 always store 10 keys to trigger the backup frequency of snapshotting
Manual data backup
Save directly after storing the data
127.0.0.1:6379> save
Data recovery needs to stop the redis service first killall redis-server shutdown redis-cli
If you need to restore data, just move the backup file (dump.rdb) to the redis installation directory and start the service
server08 bin]# cp /root/dump.rdb
Restart the service and the data will be restored
2, append only file
aof backup frequency
# appendfsync always //Forcibly write to disk every time a write command is received, the slowest, but
It guarantees complete persistence and is not recommended
appendfsync everysec // Forced to write to disk once per second, in terms of performance and persistence
A good compromise, recommended (keep a backup)
#appendfsync no //Completely depends on os, the performance is the best, and the persistence is not guaranteed
①Open aof
After enabling aof, the data in the previous redis will be lost
appendfilename “appendonly.aof” //data storage location
Summarize:
Snapshotting is used for general data persistence, high efficiency, and convenient data migration
aof is suitable for backup and data real-time backup requirements
6. Case use
1. Master-slave mode
1. Master configuration
shell > vim /usr/local/redis/bin/redis.conf
Enable monitoring, the network card for network interaction with other servers in the network, default eth0
The ip of bind refers to the ip that other hosts need to communicate with this host (the ip of this machine’s external communication)
master:192.168.17.107
Restart the server and check if it starts successfully
./redis-cli -h 192.168.17.107 slave remote connection master
2. slave configuration
vim /usr/local/redis/bin/redis.conf
yy copy the line where the cursor is located, p paste it to the line where the cursor is located n look down N look up/find content
Before redis5.0 version is to modify slaveof
Restart the server and check if it starts successfully
The slave server does not allow write operations, the configuration file is set
2. Security configuration
Configure the remote connection password for the master
Tip: If the password restriction is enabled, you need to fill in the master password in the slave configuration to build the master-slave
3. PHP extension installation
To view phpinfo, you need to write a php file with the following content
<?php
phpinfo();
?>
The phpinfo() function outputs information about the PHP configuration.
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session stored in redis
In the same way as the previous way of storing sessions in memcached, storing sessions in redis can also realize session sharing and single sign-on (sso) operations.
2. Nginx + lua + redis implement access attack blacklist WAF
https://www.cnblogs.com/huligong1234/p/4163832.html
①The installation of openresty is consistent with the previous installation
Calculate the number of visits to the same ip on the load balancing server through the lua script, and add it to the blacklist if there are too many consecutive visits
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