---
title: Redis — Database
date: 2026-10-18
time: 12:00
model: admin
category: programs
author_type: human
summary: An in-memory data structure server that handles caching, sessions, real-time analytics, and vector search as a database.
tags: program, Database and server operations, redis
---

An in-memory data structure server used as a database for caching and real-time analytics

## Basic Information

| Program name | Redis (Redis) |
| --- | --- |
| One-line introduction | An in-memory data structure server used as a database for caching and real-time analytics |
| Development and maintenance | Redis Ltd. |
| Official homepage | https://redis.io/ |
| Official documentation | https://redis.io/docs/latest/ |
| Official download | https://redis.io/docs/latest/operate/oss_and_stack/install/install-redis/ |
| Supported operating systems | Linux, macOS, Windows(WSL), Docker |
| License | Redis Source Available License (RSALv2) · SSPL · AGPL tri-license (as of 8.x) |
| Stable version | 8.10.2 (2026-09-17, 8.10 series) — checked 2026-10-18 |
| GitHub repository | https://github.com/redis/redis |
| Category | Database (tags: database, cache, in-memory, real-time, vector search) |

## What is this program?

Redis is an in-memory data structure server that primarily keeps and works with data in memory. It provides various structures such as strings, hashes, lists, sets, and sorted sets, and is widely used for tasks ranging from simple caching to session management, leaderboards, and real-time analytics.

In the 8.x lineup, it also provides features such as JSON, time series, and vector search. Its most common use is as a database cache layer to speed up web application responses, and in AI applications it is also used as a vector search engine.

## What problems does it solve?

- Situations where repeatedly queried data needs to be kept in memory to improve response speed
- Situations where short-lived state such as login sessions or shopping carts must be managed
- Situations where data requiring rapid updates, such as real-time aggregation or leaderboards, is present
## Key features

### Cache

Reduces database load by storing frequently read data in memory

- **Use case**: Improving web response speed
- **Result**: Fewer database queries
- **Limitation**: Expiration must be managed with TTL
### Data structures

Multiple structures such as strings, hashes, lists, sets, and sorted sets

- **Use case**: Implementing complex real-time tasks
- **Result**: Simple counters, queues, and session management
- **Limitation**: All operations depend on memory resources
### Pub/Sub

Channel-based message broadcasting

- **Use case**: Real-time notifications and event propagation
- **Result**: Immediate delivery to subscribers
- **Limitation**: Persistence strength must be configured
### Vector/JSON extensions

Provides vector search and JSON document features in 8.x

- **Use case**: AI search and document metadata management
- **Result**: A search layer for LLM applications
- **Limitation**: License for each extension must be checked
## Installation and execution

### Ubuntu / Debian (APT)

Installs the version from the distribution repository.

```
sudo apt install redis-server
```

### macOS (Homebrew)

Install with Homebrew.

```
brew install redis
```

### Docker

Run with the official container image.

```
docker run -d --name redis -p 6379:6379 redis:8-alpine
```

## Real-world usage examples

### Starting the server

After installation, start the service and check the port.

```
sudo systemctl enable --now redis-server
```

### Connecting with the CLI

Connect with redis-cli and perform simple key operations.

```
redis-cli > SET greeting hello > GET greeting
```

### Setting TTL

Assign an expiration time to a key.

```
redis-cli EXPIRE session:123 3600
```

## Advantages and limitations

### Advantages

- Extremely fast read/write performance
- Suitable for real-time tasks with various data structures
- Broad client ecosystem across languages
- Handles caching, sessions, queues, and vector search in one system
### Considerations before use

- Since data lives primarily in memory, capacity planning is important
- After 8.x, the license is no longer fully open source (OSI)
- Without persistence/replication settings, there is a risk of data loss during failures
## Comparison with similar programs

| Program | Characteristics | Suitable when |
| --- | --- | --- |
| PostgreSQL | Disk-based general-purpose relational DB with powerful querying | Complex transactions and queries are central |
| Memcached | Simple key-value cache with limited structures | Environments needing simple caching |
| Valkey | Redis fork with BSD license | A fully open-source license is preferred |

## Official resources and further learning

- [Official homepage](https://redis.io/) — https://redis.io/
- [Official documentation / knowledge base](https://redis.io/docs/latest/) — https://redis.io/docs/latest/
- [Official download](https://redis.io/docs/latest/operate/oss_and_stack/install/install-redis/) — https://redis.io/docs/latest/operate/oss_and_stack/install/install-redis/
- [Release notes](https://github.com/redis/redis/releases) — https://github.com/redis/redis/releases
- [Source / development resources](https://github.com/redis/redis) — https://github.com/redis/redis
Version and supported environment information is based on the official site as of 2026-10-18. Installation commands may vary depending on your distribution and version, so please also check the official installation documentation.

## Actual execution screenshot

Synthetic example — not an actual execution result. The screen is a synthetic example and is not an actual execution result.

![Example of storing and retrieving keys and setting TTL in Redis CLI](https://games.aidebatehub.com/assets/redis-demo.png)

Actual production server

---
Source (HTML): https://games.aidebatehub.com/programs/apps/databases/redis.html
This file is an auto-generated Markdown twin of the DevHub document.