What are the redis data structures?
#What are the data structures of redis?
Recommended: "redis video tutorial"
Strings (strings):
Storage integers (such as Counter) and string (nonsense...), some companies also use it to store serialized data such as json/pb, which is not recommended and wastes memory;
Hash table (hashes):
Storage configuration, objects (such as users, products), the advantage is that you can access some keys, which is suitable for frequently changing or some keys that require atom operations;
List ( lists):
can be used to store the latest user updates and timelines. The advantage is that it is orderly and the elements must be repeatable without deduplication;
sets ):
Unordered, unique, can be used if strict uniqueness is required;
Sorted sets:
The ordered version of the collection is very easy to use and can be considered for complex scenarios such as ranking;
Bitmaps:
This is not new The data type can only operate on the string type in the form of a single bit, but has not been actually used. Many people on the Internet use bitmaps for active user statistics and user sign-in functions, and the performance is much higher than loading the database.
Counter (hyperloglogs, translation to be determined):
Like the name, adding an element only records the number of elements, and does not store the element itself, saving space and avoiding repeated count , this feeling can be realized directly by using incr;
Geographic space (geospatial indexes):
is used for geographical location queries, such as the distance between two points, How many elements are there near a point is suitable for scenarios where the point is relatively fixed, or where only the current location is considered. It is not suitable for situations such as nearby people. First, the points within a certain period of time need to be considered, and second, the points are frequently updated, which is stressful. bigger.
The above is the detailed content of What are the redis data structures?. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics



Redis cluster mode deploys Redis instances to multiple servers through sharding, improving scalability and availability. The construction steps are as follows: Create odd Redis instances with different ports; Create 3 sentinel instances, monitor Redis instances and failover; configure sentinel configuration files, add monitoring Redis instance information and failover settings; configure Redis instance configuration files, enable cluster mode and specify the cluster information file path; create nodes.conf file, containing information of each Redis instance; start the cluster, execute the create command to create a cluster and specify the number of replicas; log in to the cluster to execute the CLUSTER INFO command to verify the cluster status; make

How to clear Redis data: Use the FLUSHALL command to clear all key values. Use the FLUSHDB command to clear the key value of the currently selected database. Use SELECT to switch databases, and then use FLUSHDB to clear multiple databases. Use the DEL command to delete a specific key. Use the redis-cli tool to clear the data.

To read a queue from Redis, you need to get the queue name, read the elements using the LPOP command, and process the empty queue. The specific steps are as follows: Get the queue name: name it with the prefix of "queue:" such as "queue:my-queue". Use the LPOP command: Eject the element from the head of the queue and return its value, such as LPOP queue:my-queue. Processing empty queues: If the queue is empty, LPOP returns nil, and you can check whether the queue exists before reading the element.

Using the Redis directive requires the following steps: Open the Redis client. Enter the command (verb key value). Provides the required parameters (varies from instruction to instruction). Press Enter to execute the command. Redis returns a response indicating the result of the operation (usually OK or -ERR).

Redis uses a single threaded architecture to provide high performance, simplicity, and consistency. It utilizes I/O multiplexing, event loops, non-blocking I/O, and shared memory to improve concurrency, but with limitations of concurrency limitations, single point of failure, and unsuitable for write-intensive workloads.

Using Redis to lock operations requires obtaining the lock through the SETNX command, and then using the EXPIRE command to set the expiration time. The specific steps are: (1) Use the SETNX command to try to set a key-value pair; (2) Use the EXPIRE command to set the expiration time for the lock; (3) Use the DEL command to delete the lock when the lock is no longer needed.

Redis uses hash tables to store data and supports data structures such as strings, lists, hash tables, collections and ordered collections. Redis persists data through snapshots (RDB) and append write-only (AOF) mechanisms. Redis uses master-slave replication to improve data availability. Redis uses a single-threaded event loop to handle connections and commands to ensure data atomicity and consistency. Redis sets the expiration time for the key and uses the lazy delete mechanism to delete the expiration key.

Question: How to view the Redis server version? Use the command line tool redis-cli --version to view the version of the connected server. Use the INFO server command to view the server's internal version and need to parse and return information. In a cluster environment, check the version consistency of each node and can be automatically checked using scripts. Use scripts to automate viewing versions, such as connecting with Python scripts and printing version information.
