mysql - how to check HikariCP connection pooling is working or not in Java?

Question

I have written following properties in my configuration files I am using Log4j in my application When I am running a project.

I am getting following message.does that mean connection pooling is configured in my project? if not then how it will be?

INFO: internal.ConnectionProviderInitiator - HHH000130: Instantiating explicit connection provider: com.zaxxer.hikari.hibernate.HikariConnectionProvider

I have referred following link also

link here

Datasource settings

hibernate.datasource.driver-class-name=com.mysql.jdbc.Driver
hibernate.datasource.url=jdbc:mysql://localhost:3306/mydb
hibernate.datasource.username=root
hibernate.datasource.password=root

HikariCP Settings

hibernate.hikari.dataSource.url=jdbc:mysql://localhost:3306/mydb
hibernate.hikari.idleTimeout=10
hibernate.hikari.maximumPoolSize=30
hibernate.hikari.minimumIdle=15
hibernate.connection.provider_class=com.zaxxer.hikari.hibernate.HikariConnectionProvider
hibernate.hikari.dataSourceClassName=com.mysql.jdbc.jdbc2.optional.MysqlDataSource

Answer 1

First, configuration is no consistent since maximum < minimumIdle. Those should be set at most to the same value.

hibernate.hikari.maximumPoolSize=10
hibernate.hikari.minimumIdle=10

If the pools is working you should see 10 ESTABLISHED connections to port 3306 (or mssql 1433 in the example below).

lsof -nP -i :1433 -sTCP:ESTABLISHED
COMMAND  PID       USER   FD   TYPE  DEVICE SIZE/OFF NODE NAME
java    1596 lmc  260u  IPv6 1624799      0t0  TCP 127.0.0.1:43022->127.0.0.1:1433 (ESTABLISHED)
java    1596 lmc  265u  IPv6 1626072      0t0  TCP 127.0.0.1:43026->127.0.0.1:1433 (ESTABLISHED)
java    1596 lmc  266u  IPv6 1630933      0t0  TCP 127.0.0.1:43030->127.0.0.1:1433 (ESTABLISHED)
java    1596 lmc  267u  IPv6 1631705      0t0  TCP 127.0.0.1:43034->127.0.0.1:1433 (ESTABLISHED)
java    1596 lmc  268u  IPv6 1632268      0t0  TCP 127.0.0.1:43038->127.0.0.1:1433 (ESTABLISHED)
java    1596 lmc  269u  IPv6 1632273      0t0  TCP 127.0.0.1:43042->127.0.0.1:1433 (ESTABLISHED)
java    1596 lmc  270u  IPv6 1632278      0t0  TCP 127.0.0.1:43046->127.0.0.1:1433 (ESTABLISHED)

Using ss (socket statistics)

ss -46 -np state established dport = :1433 | grep 'java' | sort -r -k 3,3 | nl
     1  tcp    0       0          [::ffff:127.0.0.1]:43158     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=273))                                               
     2  tcp    0       0          [::ffff:127.0.0.1]:43154     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=272))                                               
     3  tcp    0       0          [::ffff:127.0.0.1]:43150     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=271))                                               
     4  tcp    0       0          [::ffff:127.0.0.1]:43142     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=270))                                               
     5  tcp    0       0          [::ffff:127.0.0.1]:43138     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=269))                                               
     6  tcp    0       0          [::ffff:127.0.0.1]:43134     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=268))                                               
     7  tcp    0       0          [::ffff:127.0.0.1]:43130     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=267))                                               
     8  tcp    0       0          [::ffff:127.0.0.1]:43126     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=266))                                               
     9  tcp    0       0          [::ffff:127.0.0.1]:43122     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=265))                                               
    10  tcp    0       0          [::ffff:127.0.0.1]:43118     [::ffff:127.0.0.1]:1433   users:(("java",pid=1596,fd=260))

Using netstat (deprecated on some distros in favor of ss)

netstat -ant | grep 3306
tcp        0      0 127.0.0.1:41722     127.0.0.1:3306      ESTABLISHED 
tcp        0      0 127.0.0.1:41730     127.0.0.1:3306      ESTABLISHED 
tcp        0      0 127.0.0.1:41728     127.0.0.1:3306      ESTABLISHED 
tcp        0      0 127.0.0.1:41726     127.0.0.1:3306      ESTABLISHED 
tcp        0      0 127.0.0.1:41716     127.0.0.1:3306      ESTABLISHED 
tcp        0      0 127.0.0.1:41732     127.0.0.1:3306      ESTABLISHED 
tcp        0      0 127.0.0.1:41720     127.0.0.1:3306      ESTABLISHED 
tcp        0      0 127.0.0.1:41736     127.0.0.1:3306      ESTABLISHED 
tcp        0      0 127.0.0.1:41718     127.0.0.1:3306      ESTABLISHED 
tcp        0      0 127.0.0.1:41724     127.0.0.1:3306      ESTABLISHED