HikariDataSource cannot be initialized at application startup

Thanks for the update, I am with you now. I got a little bit confused as I thought this was happening by default as well.

Let’s take a step back. This problem has nothing to do with lazy initialization. As I’ve indicated above, this feature is disabled by default. What’s happening is that the connection pool for the DataSource (Hikari) is created but nothing is requiring a Connection. The connection pool does not attempt to reach the database until a connection is requested.

Adding the following bean is enough to force validation on startup:

@Bean
public ApplicationRunner validateDataSource(DataSource dataSource) {
	return args -> {
		try (Connection connection = dataSource.getConnection()) {
		}
	};
}

It looks like your other projects are not affected and the Hikari pool is starting when the application starts. Can you check the differences with the samples you’ve attached?

Also flagging for team attention as I don’t know what the next steps for this one should be.

@snicoll Thank you for the example.

    @Bean
    public ApplicationRunner runner(DataSource dataSource) {
        return args -> {
            log.info("dataSource: {}", dataSource);
            Connection connection = dataSource.getConnection();
            log.info("connection: {}", connection);
        };
    }

I added this code. When this code is run, a connection pool is created. It’s really fun.