As @swanliu pointed out it is due to a bad connection.
However before adjusting the server timing and client timeout , I would first try and use a better connection pooling strategy.
Hibernate itself admits that its connection pooling strategy is minimal
Hibernate’s own connection pooling algorithm is, however, quite
rudimentary. It is intended to help you get started and is not
intended for use in a production system, or even for performance
testing. You should use a third party pool for best performance and
stability. Just replace the hibernate.connection.pool_size property
with connection pool specific settings. This will turn off Hibernate’s
internal pool. For example, you might like to use c3p0.
As stated in Reference : http://docs.jboss.org/hibernate/core/3.3/reference/en/html/session-configuration.html
I personally use
C3P0. however there are other alternatives available including
Below is a minimal configuration of C3P0 used in my application:
<property name="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property> <property name="c3p0.acquire_increment">1</property> <property name="c3p0.idle_test_period">100</property> <!-- seconds --> <property name="c3p0.max_size">100</property> <property name="c3p0.max_statements">0</property> <property name="c3p0.min_size">10</property> <property name="c3p0.timeout">1800</property> <!-- seconds -->
By default, pools will never expire Connections. If you wish
Connections to be expired over time in order to maintain “freshness”,
set maxIdleTime and/or maxConnectionAge. maxIdleTime defines how many
seconds a Connection should be permitted to go unused before being
culled from the pool. maxConnectionAge forces the pool to cull any
Connections that were acquired from the database more than the set
number of seconds in the past.
As stated in Reference : http://www.mchange.com/projects/c3p0/index.html#managing_pool_size
I updated the configuration file (Reference), as I had just copy pasted the one for my project earlier.
The timeout should ideally solve the problem, If that doesn’t work for you there is an expensive solution which I think you could have a look at:
Create a file “c3p0.properties” which must be in the root of the classpath (i.e. no way to override it for particular parts of the application). (Reference)
# c3p0.properties c3p0.testConnectionOnCheckout=true
With this configuration each connection is tested before being used. It however might affect the performance of the site.