PHP数据缓存策略与更新模式

PHP数据缓存策略与更新模式缓存是提升应用性能最有效的手段。今天说说各种缓存策略和缓存更新模式。旁路缓存是最常用的模式。phpclass CacheAside{private Redis $redis;private PDO $pdo;public function __construct(Redis $redis, PDO $pdo){$this-redis $redis;$this-pdo $pdo;}public function get(string $key, callable $loader, int $ttl 3600): mixed{$cached $this-redis-get($key);if ($cached ! false) return unserialize($cached);$value $loader();$this-redis-setex($key, $ttl, serialize($value));return $value;}public function delete(string $key): void{$this-redis-del($key);}}?先更新数据库后删除缓存的策略。phpclass CacheConsistency{private Redis $redis;private PDO $pdo;public function updateUser(int $id, array $data): void{// 先更新数据库$sets [];$params [];foreach ($data as $key $value) {$sets[] {$key} ?;$params[] $value;}$params[] $id;$this-pdo-prepare(UPDATE users SET . implode(, , $sets) . WHERE id ?)-execute($params);// 再删除缓存$this-redis-del(user:{$id});}}?缓存穿透、击穿、雪崩的防护。phpclass CacheProtection{private Redis $redis;public function __construct(Redis $redis){$this-redis $redis;}// 防止缓存穿透public function get(string $key, callable $loader, int $ttl 3600): mixed{$cached $this-redis-get($key);if ($cached NULL) return null;if ($cached ! false) return unserialize($cached);$value $loader();if ($value null) {$this-redis-setex($key, 60, NULL);} else {$this-redis-setex($key, $ttl, serialize($value));}return $value;}// 防止缓存击穿public function getWithLock(string $key, callable $loader, int $ttl 3600): mixed{$cached $this-redis-get($key);if ($cached ! false) return unserialize($cached);$lockKey lock:{$key};if ($this-redis-setnx($lockKey, 1)) {$this-redis-expire($lockKey, 10);$value $loader();$this-redis-setex($key, $ttl rand(0, 300), serialize($value));$this-redis-del($lockKey);return $value;}usleep(100000);return $this-getWithLock($key, $loader, $ttl);}}?缓存在提升性能方面立竿见影。但不是所有数据都适合缓存。频繁变化的数据、每次请求都不同的数据、对实时性要求高的数据就不适合缓存。先分析业务场景再选择合适的缓存策略效果才会好。