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Default HikariCP connection pool starting Spring Boot application

I’m using version: 2.1.6.RELEASE form Spring Boot in my pom.xml-dependencies. To connect to my database I put following in

spring.datasource.url= jdbc:postgresql://

When checking the amount of connections in postgresql with:

SELECT * FROM pg_stat_activity;

I see each time I start the application exactly 10 connections are made. They almost all have the same query:

SET application_name = 'PostgreSQL JDBC Driver'

Is there a way to prevent the application of making that many connections? Should I make my own pool-configuration? What resource in my Java-application does initialize these connections?

The only thing I can think of is that I create EntityManager(s) with the @Autowired annotation, EntityManager from:


But I read you should only close the connection this makes when using an EntityManagerFactory. The annotation should close the connection.

If you would require more info, I could edit my post



That’s no a connection leak but the desired behavior. Spring Boot Data uses HikariCP as a connection pool.

You can configure the max pool size as property. For example: