Memcached

Definition

Memcached is an open-source, distributed memory caching system that is designed to speed up dynamic web applications by alleviating database load. It does this by temporarily storing data in memory, allowing for faster retrieval and reducing the need for repeated database queries. This makes it particularly useful in distributed computing environments where multiple servers need to access shared data quickly and efficiently.

5 Must Know Facts For Your Next Test

1. Memcached was originally developed at LiveJournal in 2003 to improve the performance of their website by reducing database load.
2. It operates on a key-value storage model, where data is stored and accessed using unique keys, enabling fast retrieval.
3. Memcached is designed to be simple and fast, providing a multi-threaded architecture that allows it to handle thousands of concurrent connections.
4. Data stored in memcached is ephemeral, meaning it does not persist across server restarts; it is intended for temporary storage only.
5. It can be deployed across multiple servers in a distributed environment, allowing for scalability and redundancy in caching strategies.

Review Questions

• How does memcached improve the performance of web applications in a distributed computing environment?
  • Memcached enhances the performance of web applications by reducing the load on databases through caching frequently accessed data in memory. This allows for quicker data retrieval, as the application can bypass repeated database queries and access cached results instead. In a distributed computing environment, where multiple servers may need access to shared data, memcached ensures that this data can be retrieved rapidly, leading to improved overall application responsiveness.
• Discuss the architecture of memcached and how its multi-threaded nature contributes to its efficiency.
  • Memcached features a multi-threaded architecture that enables it to handle thousands of simultaneous connections from various clients. Each thread can manage separate requests concurrently, allowing for efficient use of system resources and minimizing response times. This design choice not only enhances performance but also ensures that memcached can scale effectively as demand increases, making it suitable for high-traffic environments.
• Evaluate the trade-offs involved in using memcached for caching data compared to traditional database systems.
  • Using memcached for caching introduces several trade-offs when compared to traditional database systems. On one hand, memcached offers significant speed improvements for read operations by providing rapid access to frequently requested data stored in memory. However, since the data is not persistent and is lost when servers restart, it requires careful management of cache invalidation and refreshing strategies. Additionally, while memcached reduces database load, developers must balance caching against potential stale data issues and ensure that important transactional integrity is maintained within the underlying database.

Related terms

Caching: A technique that stores copies of frequently accessed data in a temporary storage area to speed up future requests for that data.

Distributed System: A model in which components located on networked computers communicate and coordinate their actions by passing messages.

NoSQL Database: A type of database designed to store and retrieve data in a way that is different from traditional relational databases, often supporting unstructured or semi-structured data.