Remote Dictionary Service

Overview

• Primary Focus: Speed. It is used when extremely high speed is required.
• A type of NoSQL database designed in a key:value format. It is utilized when more than just a key-value pair is needed.
• Optional Disk Storage: Redis can write to disk optionally. It is often used where the dataset is not critical. Redis stores data in memory, which imposes significant memory constraints.
  • Memory Usage:
    • An empty instance uses 1 MB of memory.
    • 1 million key-value string pairs use approximately 100 MB of memory.

Supported Data Types

1. String
2. Hash
3. List
4. Set
5. Sorted Set
6. Geospatial Index
7. HyperLogLog

Use Cases

1. Database
2. Caching Layer
3. Message Broker

Where It Should Not Be Used

• Redis is not a relational database. However, it can be used as a layer to define relationships for such database types.
• Its best use case is handling datasets with a predictable size that grows rapidly, requiring speed.

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Usage Scenarios

• Caching Mechanisms
• Pub/Sub
• Preventing and Delaying Queues
• Short-lived Data
• Counting Comments
• Analyzing Real Data
• Storing Unique Data

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Scaling Redis

Persistence

Redis provides two persistence mechanisms:

1. RDB (Redis Database Snapshots)
2. AOF (Append-Only Files)

Replication

• A single Redis instance acts as the master.
• Other instances are slaves, serving as copies of the master.
• Clients can connect to either master or slave instances.
• By default, slaves are read-only.

Partitioning

• Data can be split and distributed across instances.

Failover

• Manual
• Automatic: Managed by Redis Sentinel for master-slave topologies.

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Example: Setting up Redis with .Net Core

Running a Redis Container

To start a Redis container using Docker, execute the following command:

docker run --name my-redis -p 6379:6379 -d redis

Create a Web API Project

dotnet new webapi -n "CachingWebApi"