Hikari connection pool creates two connection after starting

Question

I use Hikary connection pool with following settings:

  HikariDataSource dataSource = new HikariDataSource();
        dataSource.setMinimumIdle(0);
        dataSource.setMaximumPoolSize(Integer.MAX_VALUE);
        dataSource.setJdbcUrl(jdbcConnectionString);
        dataSource.setConnectionTestQuery("select 1");
        dataSource.setIdleTimeout(TimeUnit.SECONDS.toMillis(60));
    dataSource.getConnection();

After getConnection() hikari try to get 2 connections to instance, but put in connection pool just one connection. How can I fix it? The hikari version is 3.4.0

Answer 1

I found the answer. Hikari creates first connection in checkFailFast method. I update this comment when find how to disable this method. The checkFailFast doesn't work if initializationFailTimeout<0. It helps me