spring-boot web app loses ability to connect to MySQL / RDS after a while

Question

I have a normal spring boot 1.2.x web app with an embedded Tomcat 7.x container and connected to an RDS instance (running MySQL 5.6). If the application is idle for a period

Answer 1

If you are using auto-configuration to define RDS connection from the property file like this:

cloud.aws.rds.testdb.password=testdbpwd
cloud.aws.rds.testdb.username=testdbuser
cloud.aws.rds.testdb.databaseName=testdb

spring boot datasource auto-configuration will not work even you put these(or tomcat datasource conf) to your configuration file:

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.test-on-borrow: true
spring.datasource.validation-query: SELECT 1 FROM DUAL
spring.datasource.log-validation-errors: true

I think this is the reason why you cannot validate your connections in the pool, before using them.

You need to override postProcessAfterInitialization method to set pool properties of the TomcatJdbcDataSourceFactory bean like this:

@Component
public class PoolConfiguration implements BeanPostProcessor {

@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
    if (bean instanceof TomcatJdbcDataSourceFactory) {
        TomcatJdbcDataSourceFactory tomcatJdbcDataSourceFactory = (TomcatJdbcDataSourceFactory) bean;
        tomcatJdbcDataSourceFactory.setTestOnBorrow(true);
        tomcatJdbcDataSourceFactory.setTestWhileIdle(true);
        tomcatJdbcDataSourceFactory.setValidationQuery("SELECT 1");
    }
    return bean;
}
}

I could not find any other solution for this.By the way this might be a bug of spring-cloud-aws-autoconfigure packet.

Good Luck!

Answer 2

Try using this as well

spring.datasource.test-while-idle=true
spring.datasource.validation-interval=5000