Grails app is hanging randomly

Question

I have noticed the past couple of weeks that every once in awhile my Grails app will hang on a request. There is nothing in the logs, no exceptions/stack. Also, the page doesn't time out, it just attempts to load without end. I have been unable to determine how to definitely reproduce this problem and that's why I say it appears to be random. My first inclination is that it has something to do with the database connection or pooling but I wanted to see if anyone else has seen this problem.

I am running Grails 1.3.1 with MySQL 5.1.37

Also, here is the relevant snippet of my DataSource.groovy file.

dataSource {
pooled = true
driverClassName = "com.mysql.jdbc.Driver"
username = "root"
password = ""
properties {
        timeBetweenEvictionRunsMillis = 60 * 60 * 1000
        validationQuery = "/* ping */"
        testWhileIdle = true
    }
dialect = org.hibernate.dialect.MySQLInnoDBDialect

}

Answer 1

Also consider garbage collection as a possible reason for this. You might track down things using jvisualvm, and switch to the concurrent collector.

Answer 2

I had the same problem but also sometimes outofmemory permgen error. this happens especially after redeploy of the application. there is a lot of stuff about this problem in the web - try "google" . i tried some of the suggestion that didn't work - but increase of min and max permgen memory on the JVM parameters works for me.