Redis: a powerful tool for efficiently processing user behavior data

Redis: A powerful tool for efficiently processing user behavior data, specific code examples are required

With the rapid development of Internet technology, mobile Internet, Internet of Things, artificial intelligence and other emerging With the rise of technology, the amount of data has reached staggering levels, so the requirements for data processing capabilities are getting higher and higher. Redis is a high-speed cache system. It has been widely used in enterprise-level applications because of its high efficiency, simplicity, stability, and good scalability. The most important application scenario is the processing of user behavior data. This article will start from the perspective of Redis. Application scenarios, advantages and disadvantages, specific usage methods, and code examples are introduced in detail.

1. Redis application scenarios

Redis has a wide range of application scenarios, and is especially suitable for processing and analyzing user behavior data. These data do not require long-term storage, but still require efficient reading and writing and Fast processing of data, such as:

1. Counter: For example, counting website PV, UV, etc., Redis can be used to operate faster and more conveniently.

2. Ranking: For example, the ranking of popular articles on the website, the ranking of articles with the most comments, etc.

3. Message Queue: Redis’s list, pub/sub and other functions are very suitable for implementing message queues.

4. Set and zset among the basic data types are often used for label calculation and ranking statistics.

2. Advantages and Disadvantages of Redis

1. Advantages: Redis has very good performance, has fast reading and writing capabilities, and supports multiple data types, so it can handle users well Behavioral data; and Redis has a wide range of application scenarios and is very suitable for use in high-concurrency scenarios. In addition, Redis also supports master-slave replication, persistence, Lua scripts and other functions to ensure data stability, scalability and high degree of customization.

2. Disadvantages: The main disadvantage of Redis is that the data does not have long-term storage capabilities and does not support transactions, so it cannot completely replace the relational database. In addition, since Redis swaps data to disk when memory is low, performance degradation may occur.

3. Specific usage of Redis

1. Installation of Redis

Redis can be installed on various operating systems, but for convenience in this article, we use Ubuntu Take the system as an example to install Redis.

First you need to install the following dependencies:

sudo apt-get install -y build-essential tcl

Then download the latest Redis stable version from the official website (here we use v5. 0.8 as an example):

wget http://download.redis.io/releases/redis-5.0.8.tar.gz

Decompression:

tar xzf redis-5.0.8.tar.gz

Enter the decompressed directory:

cd redis-5.0.8

Compile:

make

After the compilation is completed, execute the following command to install:

sudo make install

After the installation is completed, you can run redis-server. Execute the following command to start:

redis-server

By default, Redis will listen on port 6379. You can use the following command to test:

redis-cli ping

If PONG is output, it means that Redis has started successfully.

2.Redis data types

Redis supports multiple data types, including string, hash, list, set, zset, etc.

1) String type

The string data type is the simplest data type and is often used to store simple key-value data, such as strings, integers, floating point numbers, etc.

The string type of Redis can set the expiration time. How to use:

Set key-value

set mykey "hello"

Set the expiration time

expire mykey 10

Get the value

get mykey

2) Hash type

The hash data type can store multiple key-value pairs, Each key-value pair has a key and value, and the hash type is suitable for storing structured data, such as user information, product information, etc.

Usage:

Set key-value

hset userinfo uid 1001

Get value

hget userinfo uid

3) List type

The list data type can store a series of ordered elements and can be understood as a queue, supporting adding and popping elements from both ends, such as message queue, task queue, etc. Usage:

Add elements from the left end

lpush mylist "a"

Add elements from the right end

rpush mylist "b"

Get the list length

llen mylist

Pop elements from the left end

lpop mylist

Pop elements from the right end

rpop mylist

4) Set type

The set data type is a set of non-repeating elements. The elements in the set are unordered and non-repeating. Usage scenarios include user tags, event tags, etc. Usage:

Add elements to set

sadd myset "a"

Get the number of elements in set

scard myset

Judge whether the element exists

sismember myset "a"

Get all elements in the set

smembers myset

5)zset type

## The #zset data type is an ordered set of elements. Usage scenarios include rankings, popular lists, etc. The elements of zset need a score to be sorted. The higher the score, the higher the score. Usage:

Add elements to zset

zadd myzset 1 "a"

zadd myzset 2 "b"

Get the element score

zscore myzset "a"

Get ranking

zrank myzset "a"

Get the first n elements

zrange myzset 0 1

3. The core functions of Redis

Redis provides a variety of core functions, which we will introduce separately below.

1) Counter

Redis’ counter is very suitable for counting PV, UV, etc. Use the following command:

Increase counter

incr mycounter

Get counter

get mycounter

2) Ranking list

The zset type of Redis is very suitable for implementing the ranking list, use the following command:

Add Element

zadd myranking 1000 "user1"

Get ranking

zrevrange myranking 0 10 withscores

3) Publish subscription

Redis The pub/sub function is very suitable for message push and so on.

Publisher:

Connect to Redis

redis-cli

Publish message

publish mychannel "Hello Redis"

Subscriber:

Connect to Redis

redis-cli

Open subscription

subscribe mychannel

4) Lua script

Redis supports Lua scripts and can be used to implement more complex logic.

Execute Lua script

eval "return redis.call('get','mykey')" 0

4. Redis code example

Let's take the article comment function as an example to introduce how to use Redis to store and process user behavior data.

1. Initialization of Redis

Using Python language, you first need to install the redis-py module:

pip install redis

Then we need to perform Redis Initialization:

import redis
redis_client = redis.Redis(host='localhost', port=6379, db=0)

If you need to use the publish and subscribe function of Redis, then Need to use Redis class:

redis_pubsub = redis.Redis(host='localhost', port=6379, db=0, decode_responses=True)
pubsub = redis_pubsub.pubsub(ignore_subscribe_messages=True)

2. Use of counters

Use Redis counters to count the PV and UV of articles. The code is as follows:

Increase the PV counter

redis_client. incr('article:101:pv')

Increase UV counter

redis_client.pfadd('article:101:uv', 'user1', 'user2', 'user2', ' user3')

Get the value of the PV counter

redis_client.get('article:101:pv')

Get the approximate value of the UV counter

redis_client .pfcount('article:101:uv')

3. Use of publish and subscribe

Use the publish and subscribe function of Redis to realize real-time notification of article comments.

Publisher：

redis_client.publish('article:101:comment', 'new comment')

Subscriber：

class CommentSubscriber:

def __init__(self):
    self.redis_pubsub = redis.Redis(host='localhost', port=6379, db=0, decode_responses=True)
    self.pubsub = self.redis_pubsub.pubsub(ignore_subscribe_messages=True)
    self.pubsub.subscribe(['article:101:comment'])
    self.is_subscribed = True

def listen(self):
    while self.is_subscribed:
        try:
            for item in self.pubsub.listen():
                if not self.is_subscribed:
                    break
                print(item)
        except redis.ConnectionError:
            time.sleep(1)

def stop(self):
    self.is_subscribed = False
    self.pubsub.unsubscribe(['article:101:comment'])

This article aims to introduce how Redis can efficiently process user behavior data. It mainly introduces in detail the application scenarios, advantages and disadvantages, specific usage methods and code examples of Redis. Through studying this article, I believe that everyone has a deeper understanding of Redis. I hope that you can better apply Redis to process user behavior data in your future work, so as to better serve our users.

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