cause of no operations allowed after connection closed error?

Question

I am using grails 3.3.9 to build a sample hello app. When the app is deployed it works fine. When i check after a day or so the app has already crashed. Checking the logs, i see an error "no operations allowed after connection closed.". Looks like at some point the mysql database connection is broken.

Here is the database configuration i am using in application.yml

I appreciate any insight into why does connection to database get closed automatically after a while. How can i prevent it? Thanks for the feedbacks.

Answer 1

I added the following for production and so far the error hasn't recurred.

 properties:
                jmxEnabled: true
                initialSize: 5
                maxActive: 50
                minIdle: 5
                maxIdle: 25
                maxWait: 10000
                maxAge: 600000
                timeBetweenEvictionRunsMillis: 5000
                minEvictableIdleTimeMillis: 60000
                validationQuery: SELECT 1
                validationQueryTimeout: 3
                validationInterval: 15000
                testOnBorrow: true
                testWhileIdle: true
                testOnReturn: false
                jdbcInterceptors: ConnectionState
                defaultTransactionIsolation: 2 # TRANSACTION_READ_COMMITTED