What is Redis? Its capabilities and features.

Redis, short for Remote Dictionary Server, is an open-source, in-memory NoSQL key/value database. It is widely used to save sessions in Magento 2 or the application cache or for fast data retrieval.

By storing data in memory instead of on disk or SSD, Redis offers exceptional speed, reliability, and performance, making it ideal for real-time applications.

In real-world scenarios, when an application depends on external data sources, the latency of those sources can create performance bottlenecks, especially in high-traffic and large-scale applications.

Redis addresses this issue by storing data in memory, placing it physically closer to the application’s processing unit, significantly reducing latency and improving performance.

Redis cache sessions

Unlike other NoSQL databases, Redis stores data in the main memory, which helps it to perform significantly in read/write operations with better response time.

It also ensures the application’s high availability and scalability with features like replication and Redis Sentinel.

Redis Data Types and Structures
Redis provides multiple data types and structures, each optimized for specific operations:

• Strings: Simple key-value pairs for caching and counters
• Hashes: Store objects with multiple fields for user sessions or product information
• Lists: Ordered collections for queues or activity feeds
• Sets: Unordered unique elements for tags or categories
• Sorted Sets: Ordered sets with scores for leaderboards or rankings
• Bitmaps: Bit-level operations for analytics
• HyperLogLog: Cardinality estimation with minimal memory
• Geospatial Indexes: Location-based data with radius queries
• Streams: Log-like data structure for event sourcing and message queues
• JSON: Native JSON document storage (RedisJSON module)
• Vector Sets: For AI and machine learning workloads with vector similarity search

Redis features

Redis Sentinal

Redis Sentinel is a system that helps us calibrate Redis instances to be highly available for clients. It can handle monitoring, notification, and can act as a configuration provider for clients.

Redis Cluster

Redis Cluster is an implementation of Redis that can automatically split databases among various nodes. With this, you can scale Redis horizontally, ensuring high availability and performance.

Redis Persistence

It is designed to persist data on disk storage. Redis can persist datasets by taking

regular snapshots or can create backups on demand.
In the event of server failure, this will ensure database durability and integrity.

Advanced Redis Features

Redis Modules
Redis Modules extend Redis’s functionality beyond its core features. Popular modules include:

• RedisJSON: Provides native JSON data type support
• RedisTimeSeries: Enables time-series data handling
• RedisGraph: Adds graph database capabilities
• RedisBloom: Implements probabilistic data structures like Bloom filters
• RediSearch: Adds full-text search and secondary indexing capabilities

Redis Streams

Redis Streams, introduced in Redis 5.0, provides a log-like data structure that allows:

• Consumer groups for message distribution
• Message acknowledgment and pending entries list
• Automatic ID generation for entries
• Range queries by ID or time
• XREAD, XADD, XGROUP, and other commands for stream operations

Pub/Sub Messaging

Redis Pub/Sub allows for:

• Real-time messaging between applications
• Pattern-based subscriptions
• Multiple subscribers for the same channel
• Decoupling of message producers and consumers

Transactions and Lua Scripting
Redis offers:

• MULTI/EXEC blocks for grouping commands
• WATCH command for optimistic locking
• Server-side Lua scripting for atomic operations
• EVAL and EVALSHA commands for script execution
• Script caching for improved performance

Security Features
Redis security includes:

• Password authentication via the AUTH command
• TLS encryption for data in transit
• Command renaming and disabling for security hardening
• Network access control through bind configurations
• ACL (Access Control List) for fine-grained user permissions

Performance Optimization

Performance techniques include:

• Pipeline commands to reduce network round-trip
• Memory optimization tips (using hashes, ziplists, etc.)
• Configuration tuning for specific workloads
• Monitoring with INFO, SLOWLOG, and LATENCY commands
• Connection pooling and client-side optimizations

Advanced Use Cases
Redis is used for:

• Real-time leaderboards with sorted sets
• Rate limiting with INCR and EXPIRE
• Distributed locking with SETNX or Redlock algorithm
• Session store for distributed applications
• Geospatial applications with GEO commands
• Real-time analytics with bitmaps and hyperloglogs

Installing Redis on Linux

You can install Redis from the official “packages.redis.io” APT repository.

Add the repository to the APT index, update it, and then install it.

curl -fsSL https://packages.redis.io/gpg | sudo gpg --dearmor -o /usr/share/keyrings/redis-archive-keyring.gpg

echo "deb [signed-by=/usr/share/keyrings/redis-archive-keyring.gpg] https://packages.redis.io/deb $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/redis.list

sudo apt-get update

sudo apt-get install redis

You can also follow this doc about Getting started with Redis

For Magento 2 you can check How to configure Redis cache on Magento 2

If you require technical support, feel free to email us at [email protected].

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