聊聊jedis连接池的预热

序

本文主要研究一下jedis连接池的预热

预热

@Component
@Slf4j
public class JedisWarmUp implements CommandLineRunner {

    @Autowired
    JedisConnectionFactory jedisConnectionFactory;

    @Override
    public void run(String... args) throws Exception {
        GenericObjectPoolConfig poolConfig = jedisConnectionFactory.getPoolConfig();
        if (poolConfig == null) {
            return ;
        }

        try {
            DirectFieldAccessor accessor = new DirectFieldAccessor(jedisConnectionFactory);
            JedisPool jedisPool = (JedisPool) accessor.getPropertyValue("pool");
            if (jedisPool == null) {
                log.info("jedisConnectionFactory.pool is null");
                return;
            }

            int warmUpSize = poolConfig.getMaxIdle();
            warmUp(jedisPool, warmUpSize);

        } catch (Exception e) {
            log.error("warmup jedisPool error:{}", e.getMessage());
        }
    }

    private void warmUp(JedisPool jedisPool, int warmUpSize) {
        List<Jedis> warmUpList = new ArrayList<>(warmUpSize);
        for (int i=0; i< warmUpSize; i++) {
            Jedis jedis = jedisPool.getResource();
            jedis.ping();
            warmUpList.add(jedis);
        }
        warmUpList.stream().forEach(jedis -> jedis.close());
    }
}

这里取了maxIdle配置来进行预热，通过DirectFieldAccessor来获取jedisConnectionFactory对象的pool

小结

在高并发场景，通常需要对资源进行预热，比如数据库连接池、redis连接池、线程池等等，可以避免首次请求慢的问题。这里通过先从连接池借一批连接，然后归还一批连接来达到预热的目的。