CODEWITHSUNDEEP
springspring-bootamazon-rdshikaricpaws-aurora-serverless
asinkxcoswt
asinkxcoswt

Reputation: 2544

Spring Boot cannot config database connection down to zero

I am deploying my Spring Boot REST API on AWS Fargate, which connects to AWS Aurora Postgresql Serverless V1.

I have configured the Aurora to scale the ACU to 0 when idle as in the following picture, so that I am not charge too much when I don't use the API.

enter image description here

Initially, my Spring Boot App maintains 10 idle connections by default, so I have tried to make it zero by adding the this to application.properties

spring.datasource.minimumIdle=0

And then I see from AWS console that the database connection has been reduced. But it remains 1 connection forever.

enter image description here

Please help suggest if you know how to make it zero.

The Spring Boot database configuration is basically like this

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }

Edit 1

I used the suggestion in the comment to check if the connection really comes from Spring Boot.

It turns out there is no active connection but /actuator/metrics/hikaricp.connections.idle always return the value of 1

{"name":"hikaricp.connections.idle","description":"Idle connections","baseUnit":null,"measurements":[{"statistic":"VALUE","value":1.0}],"availableTags":[{"tag":"pool","values":["HikariPool-1"]}]}

And it seems does not relate to health check because I have tried running it locally and the result of /actuator/metrics/hikaricp.connections.idle remains 1.

I set logging.level.root = trace to see what is happening.

There are only 2 things keep printing in the log periodically

  1. The Hikari connection report, showing 1 idle connection
{"level":"DEBUG","ref":"|","marker":"INTERNAL","message":"HikariPool-1 - Before cleanup stats (total=1, active=0, idle=1, waiting=0)","logger":"com.zaxxer.hikari.pool.HikariPool","timestamp":"2022-06-14 16:15:16.799","thread":"HikariPool-1 housekeeper"}
{"level":"DEBUG","ref":"|","marker":"INTERNAL","message":"HikariPool-1 - After cleanup  stats (total=1, active=0, idle=1, waiting=0)","logger":"com.zaxxer.hikari.pool.HikariPool","timestamp":"2022-06-14 16:15:16.800","thread":"HikariPool-1 housekeeper"}
{"level":"DEBUG","ref":"|","marker":"INTERNAL","message":"HikariPool-1 - Fill pool skipped, pool is at sufficient level.","logger":"com.zaxxer.hikari.pool.HikariPool","timestamp":"2022-06-14 16:15:16.800","thread":"HikariPool-1 housekeeper"}
  1. Tomcat NioEndpoint, but I think it is not relevant
{"level":"DEBUG","ref":"|","marker":"INTERNAL","message":"timeout completed: keys processed=0; now=1655198117181; nextExpiration=1655198117180; keyCount=0; hasEvents=false; eval=false","logger":"org.apache.tomcat.util.net.NioEndpoint","timestamp":"2022-06-14 16:15:17.181","thread":"http-nio-8445-Poller"}

Upvotes: 1

Views: 916

Answers (1)

asinkxcoswt
asinkxcoswt

Reputation: 2544

Thanks to the suggestion in the comment, this is because of the actuator health check, which can be solved by the following settings

management.health.db.enabled=false

Upvotes: 1

Related Questions