mysql缓存数据一致性

-- 示例：使用消息队列通知缓存系统
DELIMITER $$
CREATE TRIGGER after_user_update
AFTER UPDATE ON users
FOR EACH ROW
BEGIN
    INSERT INTO cache_update_queue (table_name, record_id)
    VALUES ('users', NEW.id);
END$$
DELIMITER ;

# 示例：使用互斥锁防止缓存击穿
import redis
import time

r = redis.Redis()

def get_user(user_id):
    user = r.get(f'user:{user_id}')
    if not user:
        lock = r.lock(f'lock:user:{user_id}', timeout=10)
        if lock.acquire(blocking=False):
            try:
                user = r.get(f'user:{user_id}')
                if not user:
                    user = fetch_user_from_db(user_id)
                    r.set(f'user:{user_id}', user)
            finally:
                lock.release()
    return user

# 示例：设置不同的缓存过期时间
import random

def set_user(user_id, user_data):
    expire_time = random.randint(300, 600)  # 随机过期时间
    r.setex(f'user:{user_id}', expire_time, user_data)