Grails – automatically reconnect to MySQL datasource

Well, I’m using Grails for a huge amount of quickly hacked apps.
Most of them use MySQL for persistence, because it just works 🙂

There is one problem with the driver, though – sometimes, when nothing is happening, it allows the connections to disconnect.
It wasn’t a matter of one option somewhere, unfortunately 🙁

According to MySQL JDBC driver configuration page, it might be enough to add

autoReconnect=true

to have

    development {
        dataSource {
            dbCreate = "create-drop"
            url = "jdbc:mysql://mysqlhost/database?useUnicode=true&autoReconnect=true"
            username = ""
            password = ""
        }
    }

But it doesn’t solve it ;(
After some searching, cursing and a beer, I’ve ended up with:

dataSource {
    pooled = true
    driverClassName = "com.mysql.jdbc.Driver"
    username = "secret"
    password = "santa"

   properties {
      maxActive = 50
      maxIdle = 25
      minIdle = 1
      initialSize = 1

      numTestsPerEvictionRun = 3
      maxWait = 10000

      testOnBorrow = true
      testWhileIdle = true
      testOnReturn = true

      validationQuery = "select now()"

      minEvictableIdleTimeMillis = 1000 * 60 * 5
      timeBetweenEvictionRunsMillis = 1000 * 60 * 5
   }
}

And this has been good enough to solve my pains. Thank you grails, for making me have problems I wouldn’t otherwise have.
Nice of you to allow me to fix them pretty fast at the same time 🙂

Author: ags

bio View all posts by ags