Comparison and selection guidelines for Memcached and Redis

MEMCACHED and Redis are two open source memory caching systems. They provide a very efficient cache mechanism when dealing with high and large -scale data sets.This article will introduce the comparison of Memcached and Redis and provide you with a guide to select the cache system that is suitable for your needs. 1. Performance comparison: -Memcached: Memcached is a distributed high -speed cache system that is mainly used to reduce the reading pressure of the database.It uses simple key values to storage and distributes data to multiple servers through hash algorithms.MEMCACHED can provide very high read and write performance and low latency, and is suitable for scenarios with low consistency requirements. -Redis: Redis is a data structure server. In addition to supporting the cache function, it also provides richer data structure and functions.It supports complex data types such as string, hash table, list, collection, and orderly collection, and also provides functions such as transactions, release/subscriptions, and persistence.Redis's reading and writing performance is also very high and has low delay. 2. Data persistence: -MEMCACHED: MEMCACHED save all data in memory, and does not provide a persistence mechanism.When the server restarts or data is lost, the data needs to be loaded again from the database. -Redis: Redis supports the persistence of data, which can save data on the disk to achieve data persistence storage.It provides two persistence methods: RDB snapshots (saving data in a binary form to disk) and AOF logs (saved the operation log in an additional manner), and you can choose a suitable persistence method according to your needs. 3. Cache characteristics: -MEMCACHED: MEMCACHED is mainly used for caching data, suitable for reading more scenes.Its expiration time is manually set by developers and does not support complex data structure and operation. -Redis: Redis can not only be used as a cache system, but also as a data storage system.It provides rich data structures and operations, supports complex cache requirements, and can use the expiration time to control the validity period of cache. 4. Calling consistency: -Memcached: MEMCACHED adopts unruly consistency distributed architecture and does not provide transaction and replication mechanism.When a node fails, the data will be lost and need to be loaded again from the database. -Redis: Redis provides data persistence and master -slave replication mechanism, which can be replicated on multiple nodes to achieve high availability and data backup.It also supports transaction operations to ensure the consistency of the cache data. According to the above comparison, you can choose the appropriate cache system according to actual needs: -If you need a simple and efficient cache system to alleviate the reading pressure of the database and do not have high requirements for consistency, you can choose Memcached. -If you need a functional cache and data storage system to support complex data structure, transactions and persistence functions, you can choose Redis. Here are a sample code using Redis cache: python import redis # Redis server r = redis.Redis(host='localhost', port=6379, db=0) # Set up cache r.set('key', 'value') # 存 获 value = r.get('key') print(value) # Delete cache r.delete('key') In the above code, we used the Redis Python client to connect, set up cache, get cache, and delete cache operations.According to your actual situation, you can configure related parameters as needed, such as connection address and port number. I hope this article provides some help for you to choose Memcached or Redis cache system and choose according to actual needs to obtain cache solutions that are most suitable for your application scenarios.