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English
Cache plays a crucial role in websites and applications by significantly improving performance. As the business and user base grow, a single cache server may not handle the high concurrency load. At this point, distributed cache helps to spread the load, enhancing overall cache performance and stability.
Frequent database access and file operations increase server load, affecting application response speed and availability. Implementing caching reduces server pressure and improves response efficiency and concurrency capability.
A single cache server cannot meet large-scale access demands. Distributed cache distributes data across multiple servers, improving the cache system's performance and fault tolerance, ensuring the entire system remains stable even if one node fails.
Choosing the right technology solution is key and should be based on business needs to ensure system scalability and high availability.
Memcached and Redis are popular caching solutions with good scalability and high concurrency handling capabilities. Their characteristics are as follows:
Redis supports rich data structures such as lists, sets, and hashes, supports data persistence, cluster mode, and Lua script extensions, making it suitable for complex business scenarios.
Memcached is simpler, ideal for scenarios requiring high cache performance without persistence, with lighter deployment and usage.
Implementing Redis distributed cache requires setting up a cluster composed of multiple nodes that communicate and share caching load.
Redis uses a hash slot algorithm to distribute cache data to different nodes, achieving data sharding and load balancing.
When connecting clients to the cluster, Redis clients supporting clusters such as Cluster or Redisson can be used, facilitating data exchange and failover between nodes.
The following example shows how to connect to a Redis cluster with PHP code and add hash slots:
$redis = new Redis();
$redis->connect('127.0.0.1', 6379);
$redis->cluster('addslots', range(0, 10000));
This code connects to a Redis cluster node and assigns hash slots from 0 to 10000 to this node, ensuring balanced distribution of cached data.
Cache is vital in PHP backend development, effectively improving system performance and concurrency handling. Distributed cache enhances scalability and fault tolerance by distributing data. Redis and Memcached both have advantages, and developers should choose according to business needs. When using Redis for distributed caching, properly building cluster architecture, using appropriate clients, and writing PHP code for node management and load balancing are key to creating a high-performance caching system.
