Category: redis

Redis – Commands ”; Previous Next Redis commands are used to perform some operations on Redis server. To run commands on Redis server, you need a Redis client. Redis client is available in Redis package, which we have installed earlier. Syntax Following is the basic syntax of Redis client. $redis-cli Example Following example explains how we can start Redis client. To start Redis client, open the terminal and type the command redis-cli. This will connect to your local server and now you can run any command. $redis-cli redis 127.0.0.1:6379> redis 127.0.0.1:6379> PING PONG In the above example, we connect to Redis server running on the local machine and execute a command PING, that checks whether the server is running or not. Run Commands on the Remote Server To run commands on Redis remote server, you need to connect to the server by the same client redis-cli Syntax $ redis-cli -h host -p port -a password Example Following example shows how to connect to Redis remote server, running on host 127.0.0.1, port 6379 and has password mypass. $redis-cli -h 127.0.0.1 -p 6379 -a “mypass” redis 127.0.0.1:6379> redis 127.0.0.1:6379> PING PONG Print Page Previous Next Advertisements ”;

Redis – Keys ”; Previous Next Redis keys commands are used for managing keys in Redis. Following is the syntax for using redis keys commands. Syntax redis 127.0.0.1:6379> COMMAND KEY_NAME Example redis 127.0.0.1:6379> SET tutorialspoint redis OK redis 127.0.0.1:6379> DEL tutorialspoint (integer) 1 In the above example, DEL is the command, while tutorialspoint is the key. If the key is deleted, then the output of the command will be (integer) 1, otherwise it will be (integer) 0. Redis Keys Commands Following table lists some basic commands related to keys. Sr.No Command & Description 1 DEL key This command deletes the key, if it exists. 2 DUMP key This command returns a serialized version of the value stored at the specified key. 3 EXISTS key This command checks whether the key exists or not. 4 EXPIRE key seconds Sets the expiry of the key after the specified time. 5 EXPIREAT key timestamp Sets the expiry of the key after the specified time. Here time is in Unix timestamp format. 6 PEXPIRE key milliseconds Set the expiry of key in milliseconds. 7 PEXPIREAT key milliseconds-timestamp Sets the expiry of the key in Unix timestamp specified as milliseconds. 8 KEYS pattern Finds all keys matching the specified pattern. 9 MOVE key db Moves a key to another database. 10 PERSIST key Removes the expiration from the key. 11 PTTL key Gets the remaining time in keys expiry in milliseconds. 12 TTL key Gets the remaining time in keys expiry. 13 RANDOMKEY Returns a random key from Redis. 14 RENAME key newkey Changes the key name. 15 RENAMENX key newkey Renames the key, if a new key doesn”t exist. 16 TYPE key Returns the data type of the value stored in the key. Print Page Previous Next Advertisements ”;

Redis – Overview ”; Previous Next Redis is an open source, advanced key-value store and an apt solution for building highperformance, scalable web applications. Redis has three main peculiarities that sets it apart. Redis holds its database entirely in the memory, using the disk only for persistence. Redis has a relatively rich set of data types when compared to many key-value data stores. Redis can replicate data to any number of slaves. Redis Advantages Following are certain advantages of Redis. Exceptionally fast − Redis is very fast and can perform about 110000 SETs per second, about 81000 GETs per second. Supports rich data types − Redis natively supports most of the datatypes that developers already know such as list, set, sorted set, and hashes. This makes it easy to solve a variety of problems as we know which problem can be handled better by which data type. Operations are atomic − All Redis operations are atomic, which ensures that if two clients concurrently access, Redis server will receive the updated value. Multi-utility tool − Redis is a multi-utility tool and can be used in a number of use cases such as caching, messaging-queues (Redis natively supports Publish/Subscribe), any short-lived data in your application, such as web application sessions, web page hit counts, etc. Redis Versus Other Key-value Stores Redis is a different evolution path in the key-value DBs, where values can contain more complex data types, with atomic operations defined on those data types. Redis is an in-memory database but persistent on disk database, hence it represents a different trade off where very high write and read speed is achieved with the limitation of data sets that can”t be larger than the memory. Another advantage of in-memory databases is that the memory representation of complex data structures is much simpler to manipulate compared to the same data structure on disk. Thus, Redis can do a lot with little internal complexity. Print Page Previous Next Advertisements ”;

Redis – Environment ”; Previous Next In this chapter, you will learn about the environmental setup for Redis. Install Redis on Ubuntu To install Redis on Ubuntu, go to the terminal and type the following commands − $sudo apt-get update $sudo apt-get install redis-server This will install Redis on your machine. Start Redis $redis-server Check If Redis is Working $redis-cli This will open a redis prompt. redis 127.0.0.1:6379> In the above prompt, 127.0.0.1 is your machine”s IP address and 6379 is the port on which Redis server is running. Now type the following PING command. redis 127.0.0.1:6379> ping PONG This shows that Redis is successfully installed on your machine. Install Redis Desktop Manager on Ubuntu To install Redis desktop manager on Ubuntu, just download the package from https://redisdesktop.com/download Open the downloaded package and install it. Redis desktop manager will give you UI to manage your Redis keys and data. Print Page Previous Next Advertisements ”;

Redis – Strings ”; Previous Next Redis strings commands are used for managing string values in Redis. Following is the syntax for using Redis string commands. Syntax redis 127.0.0.1:6379> COMMAND KEY_NAME Example redis 127.0.0.1:6379> SET tutorialspoint redis OK redis 127.0.0.1:6379> GET tutorialspoint “redis” In the above example, SET and GET are the commands, while tutorialspoint is the key. Redis Strings Commands Following table lists some basic commands to manage strings in Redis. Sr.No Command & Description 1 SET key value This command sets the value at the specified key. 2 GET key Gets the value of a key. 3 GETRANGE key start end Gets a substring of the string stored at a key. 4 GETSET key value Sets the string value of a key and return its old value. 5 GETBIT key offset Returns the bit value at the offset in the string value stored at the key. 6 MGET key1 [key2..] Gets the values of all the given keys 7 SETBIT key offset value Sets or clears the bit at the offset in the string value stored at the key 8 SETEX key seconds value Sets the value with the expiry of a key 9 SETNX key value Sets the value of a key, only if the key does not exist 10 SETRANGE key offset value Overwrites the part of a string at the key starting at the specified offset 11 STRLEN key Gets the length of the value stored in a key 12 MSET key value [key value …] Sets multiple keys to multiple values 13 MSETNX key value [key value …] Sets multiple keys to multiple values, only if none of the keys exist 14 PSETEX key milliseconds value Sets the value and expiration in milliseconds of a key 15 INCR key Increments the integer value of a key by one 16 INCRBY key increment Increments the integer value of a key by the given amount 17 INCRBYFLOAT key increment Increments the float value of a key by the given amount 18 DECR key Decrements the integer value of a key by one 19 DECRBY key decrement Decrements the integer value of a key by the given number 20 APPEND key value Appends a value to a key Print Page Previous Next Advertisements ”;

Redis – Configuration ”; Previous Next In Redis, there is a configuration file (redis.conf) available at the root directory of Redis. Although you can get and set all Redis configurations by Redis CONFIG command. Syntax Following is the basic syntax of Redis CONFIG command. redis 127.0.0.1:6379> CONFIG GET CONFIG_SETTING_NAME Example redis 127.0.0.1:6379> CONFIG GET loglevel 1) “loglevel” 2) “notice” To get all configuration settings, use * in place of CONFIG_SETTING_NAME Example redis 127.0.0.1:6379> CONFIG GET * 1) “dbfilename” 2) “dump.rdb” 3) “requirepass” 4) “” 5) “masterauth” 6) “” 7) “unixsocket” 8) “” 9) “logfile” 10) “” 11) “pidfile” 12) “/var/run/redis.pid” 13) “maxmemory” 14) “0” 15) “maxmemory-samples” 16) “3” 17) “timeout” 18) “0” 19) “tcp-keepalive” 20) “0” 21) “auto-aof-rewrite-percentage” 22) “100” 23) “auto-aof-rewrite-min-size” 24) “67108864” 25) “hash-max-ziplist-entries” 26) “512” 27) “hash-max-ziplist-value” 28) “64” 29) “list-max-ziplist-entries” 30) “512” 31) “list-max-ziplist-value” 32) “64” 33) “set-max-intset-entries” 34) “512” 35) “zset-max-ziplist-entries” 36) “128” 37) “zset-max-ziplist-value” 38) “64” 39) “hll-sparse-max-bytes” 40) “3000” 41) “lua-time-limit” 42) “5000” 43) “slowlog-log-slower-than” 44) “10000” 45) “latency-monitor-threshold” 46) “0” 47) “slowlog-max-len” 48) “128” 49) “port” 50) “6379” 51) “tcp-backlog” 52) “511” 53) “databases” 54) “16” 55) “repl-ping-slave-period” 56) “10” 57) “repl-timeout” 58) “60” 59) “repl-backlog-size” 60) “1048576” 61) “repl-backlog-ttl” 62) “3600” 63) “maxclients” 64) “4064” 65) “watchdog-period” 66) “0” 67) “slave-priority” 68) “100” 69) “min-slaves-to-write” 70) “0” 71) “min-slaves-max-lag” 72) “10” 73) “hz” 74) “10” 75) “no-appendfsync-on-rewrite” 76) “no” 77) “slave-serve-stale-data” 78) “yes” 79) “slave-read-only” 80) “yes” 81) “stop-writes-on-bgsave-error” 82) “yes” 83) “daemonize” 84) “no” 85) “rdbcompression” 86) “yes” 87) “rdbchecksum” 88) “yes” 89) “activerehashing” 90) “yes” 91) “repl-disable-tcp-nodelay” 92) “no” 93) “aof-rewrite-incremental-fsync” 94) “yes” 95) “appendonly” 96) “no” 97) “dir” 98) “/home/deepak/Downloads/redis-2.8.13/src” 99) “maxmemory-policy” 100) “volatile-lru” 101) “appendfsync” 102) “everysec” 103) “save” 104) “3600 1 300 100 60 10000” 105) “loglevel” 106) “notice” 107) “client-output-buffer-limit” 108) “normal 0 0 0 slave 268435456 67108864 60 pubsub 33554432 8388608 60” 109) “unixsocketperm” 110) “0” 111) “slaveof” 112) “” 113) “notify-keyspace-events” 114) “” 115) “bind” 116) “” Edit Configuration To update configuration, you can edit redis.conf file directly or you can update configurations via CONFIG set command. Syntax Following is the basic syntax of CONFIG SET command. redis 127.0.0.1:6379> CONFIG SET CONFIG_SETTING_NAME NEW_CONFIG_VALUE Example redis 127.0.0.1:6379> CONFIG SET loglevel “notice” OK redis 127.0.0.1:6379> CONFIG GET loglevel 1) “loglevel” 2) “notice” Print Page Previous Next Advertisements ”;

Redis Tutorial PDF Version Quick Guide Resources Job Search Discussion Redis is an open source, BSD licensed, advanced key-value store. It is often referred to as a data structure server, since the keys can contain strings, hashes, lists, sets and sorted sets. Redis is written in C. This tutorial provides good understanding on Redis concepts, needed to create and deploy a highly scalable and performance-oriented system. Audience This tutorial is designed for Software Professionals who are willing to learn Redis in simple and easy steps. After completing this tutorial, you will be at an intermediate level of expertise from where you can take yourself to a higher level of expertise. Prerequisites Before proceeding with this tutorial, you should have basic knowledge of Data Structures. Print Page Previous Next Advertisements ”;

Redis – Data Types ”; Previous Next Redis supports 5 types of data types. Strings Redis string is a sequence of bytes. Strings in Redis are binary safe, meaning they have a known length not determined by any special terminating characters. Thus, you can store anything up to 512 megabytes in one string. Example redis 127.0.0.1:6379> SET name “tutorialspoint” OK redis 127.0.0.1:6379> GET name “tutorialspoint” In the above example, SET and GET are Redis commands, name is the key used in Redis and tutorialspoint is the string value that is stored in Redis. Note − A string value can be at max 512 megabytes in length. Hashes A Redis hash is a collection of key value pairs. Redis Hashes are maps between string fields and string values. Hence, they are used to represent objects. Example redis 127.0.0.1:6379> HMSET user:1 username tutorialspoint password tutorialspoint points 200 OK redis 127.0.0.1:6379> HGETALL user:1 1) “username” 2) “tutorialspoint” 3) “password” 4) “tutorialspoint” 5) “points” 6) “200” In the above example, hash data type is used to store the user”s object which contains basic information of the user. Here HMSET, HGETALL are commands for Redis, while user − 1 is the key. Every hash can store up to 232 – 1 field-value pairs (more than 4 billion). Lists Redis Lists are simply lists of strings, sorted by insertion order. You can add elements to a Redis List on the head or on the tail. Example redis 127.0.0.1:6379> lpush tutoriallist redis (integer) 1 redis 127.0.0.1:6379> lpush tutoriallist mongodb (integer) 2 redis 127.0.0.1:6379> lpush tutoriallist rabitmq (integer) 3 redis 127.0.0.1:6379> lrange tutoriallist 0 10 1) “rabitmq” 2) “mongodb” 3) “redis” The max length of a list is 232 – 1 elements (4294967295, more than 4 billion of elements per list). Sets Redis Sets are an unordered collection of strings. In Redis, you can add, remove, and test for the existence of members in O(1) time complexity. Example redis 127.0.0.1:6379> sadd tutoriallist redis (integer) 1 redis 127.0.0.1:6379> sadd tutoriallist mongodb (integer) 1 redis 127.0.0.1:6379> sadd tutoriallist rabitmq (integer) 1 redis 127.0.0.1:6379> sadd tutoriallist rabitmq (integer) 0 redis 127.0.0.1:6379> smembers tutoriallist 1) “rabitmq” 2) “mongodb” 3) “redis” Note − In the above example, rabitmq is added twice, however due to unique property of the set, it is added only once. The max number of members in a set is 232 – 1 (4294967295, more than 4 billion of members per set). Sorted Sets Redis Sorted Sets are similar to Redis Sets, non-repeating collections of Strings. The difference is, every member of a Sorted Set is associated with a score, that is used in order to take the sorted set ordered, from the smallest to the greatest score. While members are unique, the scores may be repeated. Example redis 127.0.0.1:6379> zadd tutoriallist 0 redis (integer) 1 redis 127.0.0.1:6379> zadd tutoriallist 0 mongodb (integer) 1 redis 127.0.0.1:6379> zadd tutoriallist 0 rabitmq (integer) 1 redis 127.0.0.1:6379> zadd tutoriallist 0 rabitmq (integer) 0 redis 127.0.0.1:6379> ZRANGEBYSCORE tutoriallist 0 1000 1) “redis” 2) “mongodb” 3) “rabitmq” Print Page Previous Next Advertisements ”;

Redis – Security ”; Previous Next Redis database can be secured, such that any client making a connection needs to authenticate before executing a command. To secure Redis, you need to set the password in the config file. Example Following example shows the steps to secure your Redis instance. 127.0.0.1:6379> CONFIG get requirepass 1) “requirepass” 2) “” By default, this property is blank, which means no password is set for this instance. You can change this property by executing the following command. 127.0.0.1:6379> CONFIG set requirepass “tutorialspoint” OK 127.0.0.1:6379> CONFIG get requirepass 1) “requirepass” 2) “tutorialspoint” After setting the password, if any client runs the command without authentication, then (error) NOAUTH Authentication required. error will return. Hence, the client needs to use AUTH command to authenticate himself. Syntax Following is the basic syntax of AUTH command. 127.0.0.1:6379> AUTH password Example 127.0.0.1:6379> AUTH “tutorialspoint” OK 127.0.0.1:6379> SET mykey “Test value” OK 127.0.0.1:6379> GET mykey “Test value” Print Page Previous Next Advertisements ”;