CODEWITHSUNDEEP
spring-bootredisconnection-poolingjedis
dev333
dev333

Reputation: 799

How to use JedisConfig pool efficiently without increasing number of connections more than maxtotal?

Jedis pool is not working as expected .I have mentioned active connections 10 but it is allowing even above 10 connections.

I have overridden getConnection() method from RedisConnectionFactory. This method has been called almost for 30 times for getting the connection.

I have configured the jedis config pool as mentioned below. Can some one please help me out why it is creating the connections more than the maxtotal? And can someone please help me out with the closing of jedisconnection pool as well.

@Configuration
public class RedisConfiguration {
        @Bean
        public RedisTenantDataFactory redisTenantDataFactory(){
        JedisPoolConfig poolConfig = new JedisPoolConfig();
                        poolConfig.setMaxIdle(1);
                        poolConfig.setMaxTotal(10);
                        poolConfig.setBlockWhenExhausted(true);
                        poolConfig.setMaxWaitMillis(10);
                        
                        JedisConnectionFactory jedisConnectionFactory = new 
                        JedisConnectionFactory(poolConfig);
                        jedisConnectionFactory.setHostName(redisHost);
                        jedisConnectionFactory.setUsePool(true);
                        jedisConnectionFactory.setPort(Integer.valueOf(redisPort));
    }
    
        #####
           @Bean
            public RedisTemplate<String, Object> redisTemplate(@Autowired RedisConnectionFactory redisConnectionFactory) {
                RedisTemplate<String, Object> template = new RedisTemplate<>();
                template.setConnectionFactory(redisConnectionFactory);
                template.afterPropertiesSet();
                return template;
            }
}

I have overridden getConnection() method from RedisConnectionFactory. This method has been called almost for 30 times for getting the connection.

Upvotes: 2

Views: 4871

Answers (1)

Tug Grall
Tug Grall

Reputation: 3520

It is probably a misunderstanding of the ConnectionPool behaviour. Without having the details about how you are using the pool in your application I guess.

So you pool is configured as followed:

...
poolConfig.setMaxIdle(1);
poolConfig.setMaxTotal(10);
poolConfig.setBlockWhenExhausted(true)
...

This means as you expect, you will not have more than 10 active connections from this specific pool to Redis.

You can check the number of clients (open connection) from Redis itself using RedisInsight or using the command CLIENT LIST, you will see that you will not have more than 10 connections coming from this JVM.

The fact that your see many call to getConnection() is just because your application is calling it each time a connection is needed. This does NOT means "open a new connection", this means "give me a connection from the pool", and your configuration define the behaviour, as follow:

  • poolConfig.setMaxIdle(1) => you will have at least always 1 connection open and available for your application. This is important to chose a good number since "creating a new connection" is taking time and resources. (1 is probably too low in a normal application)
  • poolConfig.setMaxTotal(10) => this mean that the pool will not have more than 10 connections open in the same time. So you MUST define what happen when you have reach 10, and your app need one. This is where
  • poolConfig.setBlockWhenExhausted(true) => This means that if you have already 10 "active" connections used by your application, and the application call getConnection(), it will "block" until one of the 10 connections is returned to the pool.

So "blocking" is probably not a very good idea... (but once again it depends of your application)

Maybe you are wondering why your application is calling the getConnection() 30 times, and why it does not stop/block at 10....

Because your code is good ;), what I mean by that your application:

1- Jedis jedis = pool.getCoonnection(); (so it takes one active connection from the pool) 2- you are using jedis connection as much as needed 3- you close the connection jedis.close() ( this does not necessary close the real connection, it returns back the connection to the pool, and the pool can reuse it or close it depending of the application/configuration)

Does it make sense?

Usually you will work with the following code

/// Jedis implements Closeable. Hence, the jedis instance will be auto-closed after the last statement.
try (Jedis jedis = pool.getResource()) {
  /// ... do stuff here ... for example
  jedis.set("foo", "bar");
  String foobar = jedis.get("foo");
  jedis.zadd("sose", 0, "car"); jedis.zadd("sose", 0, "bike"); 
  Set<String> sose = jedis.zrange("sose", 0, -1);
}
/// ... when closing your application:
pool.close()

You can find more information about JedisPool and Apache CommonPool here:

Upvotes: 5

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