Jedis Pipeline on a SentinelPool causes the server to reach max client connections

[Haris Koktsidis]

Hello,

I am creating a JedisSentinelPool 

        JedisPoolConfig poolConfig = new JedisPoolConfig();

        poolConfig.setMinIdle(100);

        poolConfig.setMaxIdle(150);

        poolConfig.setMaxTotal(200);

        poolConfig.setBlockWhenExhausted(true);

        poolConfig.setTestOnBorrow(true);

        JedisSentinelPool pool = new JedisSentinelPool(masterName, sentinels, poolConfig, pasword);

and I am getting a resource from the pool as following from the class Jedis:

public Jedis getJedis() {

       try {

           Jedis jedis = pool.getJedis();

           return jedis;

       } catch (Exception ex) {

          // Log

       }

} 

I am using pipelines in my application API to save the request in Redis as a cache. However after some time the active connections on Redis reach the cap (default: 10000) and I get the following exception:

2018-05-12 13:45:34,608 SEVERE [com.apifon.extranet.cache.client.JRedisCache] (default task-9) Exception while retrieving resource from the pool : redis.clients.jedis.exceptions.JedisException: Could not get a resource from the pool

        at redis.clients.util.Pool.getResource(Pool.java:51)

        at redis.clients.jedis.JedisSentinelPool.getResource(JedisSentinelPool.java:209)

                              ..... 

Caused by: java.util.NoSuchElementException: Unable to validate object

        at org.apache.commons.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:506)

        at org.apache.commons.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:363)

        at redis.clients.util.Pool.getResource(Pool.java:49)

        ... 62 more

In my API I am using the Redis as following:

              try (Jedis jedis = JedisManager.getJedis()) {

                        Pipeline redisPipeline = jedis.pipelined();

                        redisPipeline.multi();

                        // Ommited code

                        for (int i=0; i<10; i++) {

                                redisPipeline.hset("something".getBytes(), "somethingElse".getBytes(), byteArray);

                        }

                        // Ommited code

                        redisPipeline.exec();

                        redisPipeline.sync();

              }

I have excluded every other part of my application that I am using Redis and I still have the same result. My Jedis version is 2.9, my Java is 1.8.151 and my server is Wildfly 10.0