MySQL Connection Timeout Issue - Grails Application on Tomcat using Hibernate and ORM

Question

I have a small grails application running on Tomcat in Ubuntu on a VPS. I use MySql as my datastore and everything works fine unless I leave the application for more than ha

Answer 1

Referring to this article, you have stale connections in your DBCP connections pool that are silently dropped by OS or firewall.

The solution is to define a validation query and do a sanity check of the connection before you actually use it in your application. In grails this is actually done by modifying the grails-app/conf/spring/Resource.groovy file and add the following:

beans = {
  dataSource(BasicDataSource) {
    //run the evictor every 30 minutes and evict any connections older than 30 minutes.
    minEvictableIdleTimeMillis=1800000
    timeBetweenEvictionRunsMillis=1800000
    numTestsPerEvictionRun=3
    //test the connection while its idle, before borrow and return it
    testOnBorrow=true
    testWhileIdle=true
    testOnReturn=true
    validationQuery="SELECT 1"
  }
}