How to view keys for a specific pattern
There are two ways to view keys for a specific pattern in Redis: iterate over the database using the SCAN command, returning the keys for matching patterns until the cursor is 0. Use the KEYS command to directly return the keys of all matching patterns.
How to view keys for specific patterns in Redis
Redis provides a variety of ways to find and list keys for a specific schema. Here are the steps to achieve this:
Use the SCAN command
The SCAN command is used to iterate over the database in Redis, returning the key that matches the given pattern. Its syntax is as follows:
<code>SCAN cursor [MATCH pattern] [COUNT count]</code>
The parameters are as follows:
-
cursor
: A cursor indicating the scan status. During initial scan, set the cursor to 0. -
pattern
: The key pattern to match. Use wildcards*
to match 0 or more characters. -
count
: The maximum number of keys returned at a time.
To find the keys for matching patterns using the SCAN command:
- Set the cursor to
0
. - Run the
SCAN
command, specifying the pattern to match and the number of keys to return. - Save the returned key list and cursor.
- Repeat steps 2 and 3 until the cursor is
0
.
Use the KEYS command
The KEYS command returns all keys that match the given pattern. Its syntax is as follows:
<code>KEYS pattern</code>
where pattern
is the key pattern to match.
The steps to find the keys that match patterns using the KEYS command are as follows:
- Run the
KEYS
command to specify the pattern to match. - Save the returned key list.
Example
The following example shows how to use the SCAN command to find keys that start with "user:*" mode:
<code>SCAN 0 MATCH user:* COUNT 10</code>
This command returns the first 10 keys that start with "user:*" mode.
The following example demonstrates how to use the KEYS command to find all keys ending in .log
:
<code>KEYS *.log</code>
This command will return all keys ending in .log
.
The above is the detailed content of How to view keys for a specific pattern. 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

AI Hentai Generator
Generate AI Hentai for free.

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.

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).

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.

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.

The best way to understand Redis source code is to go step by step: get familiar with the basics of Redis. Select a specific module or function as the starting point. Start with the entry point of the module or function and view the code line by line. View the code through the function call chain. Be familiar with the underlying data structures used by Redis. Identify the algorithm used by Redis.

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.

Redis, as a message middleware, supports production-consumption models, can persist messages and ensure reliable delivery. Using Redis as the message middleware enables low latency, reliable and scalable messaging.
