Redis is an open-source, in-memory data structure store that is often used as a database, cache, and message broker. It is known for its speed and flexibility, making it popular for various use cases where fast data access and high-throughput are essential.
Here's an overview of how Redis works:
1. In-Memory Data Store:
Redis primarily operates as an in-memory data store, meaning all the data is stored in RAM. This allows Redis to achieve incredibly low read and write latencies since it doesn't need to access disk storage for most operations.
2. Key-Value Store:
Redis is a key-value store, where data is organized as key-value pairs. Each key is a unique identifier, and the associated value can be a wide range of data types, including strings, hashes, lists, sets, sorted sets, bitmaps, hyperloglogs, and more.
3. Persistence Options:
While Redis is primarily an in-memory database, it provides persistence options to save data to disk periodically or on specific events. This ensures that data is not lost in case of system restarts or failures.
4. Data Expiration:
Redis allows you to set an expiration time (time-to-live) for each key. Once the expiration time is reached, Redis automatically removes the key from the database. This feature is useful for caching and temporary data storage.
5. Built-in Data Structures:
Redis provides various data structures, such as lists, sets, and sorted sets, which enable advanced data manipulation and operations. For example, you can push and pop elements from lists, perform set operations like unions and intersections, and use sorted sets to maintain a sorted collection with unique elements.
6. Single-Threaded Architecture:
Redis employs a single-threaded event loop to handle all the client requests. This design choice simplifies the internal implementation and ensures atomicity of operations, but it also means that Redis may not fully utilize multi-core processors for a single instance.
7. Pub/Sub and Message Broker:
Redis supports a publish/subscribe (Pub/Sub) messaging paradigm. Clients can subscribe to channels and receive messages published to those channels. This makes Redis useful as a message broker in distributed systems and real-time applications.
8. High Performance:
Due to its in-memory nature and optimized data structures, Redis can deliver excellent performance for read-heavy workloads and simple data operations.
It's important to note that since Redis is an in-memory store, the size of the data it can handle is limited by the available RAM. While this limitation is essential to consider for certain use cases, Redis's speed and versatility have made it a popular choice for various applications, such as caching, session storage, real-time analytics, and task queuing, among others.
Install Redis in an Ubuntu based machine:
1. Update the package list:
Open a terminal and run the following command to ensure your package list is up to date:
sudo apt update
2. Install Redis:
Run the following command to install Redis:
sudo apt install redis-server
3. Start Redis service:
After the installation is complete, the Redis service should start automatically. You can check its status with:
sudo systemctl status redis-server
If it's not running, you can start it with:
sudo systemctl start redis-server
4. Enable Redis to start on boot:
If you want Redis to start automatically when the system boots up, enable it with:
sudo systemctl enable redis-server
5. Test the installation:
You can test that Redis is running by connecting to the server using the Redis command-line interface:
redis-cli
This should open the Redis CLI, and you can run Redis commands here. For example, try the PING command:
PING
If Redis is running correctly, it will respond with PONG.