c3p0 connection refill in tomcat - database

Question

2016-05-16 09:49:20,505 [http-bio-8080-exec-6] WARN [com.mchange.v2.c3p0.impl.DefaultConnectionTester] - SQL State '08007' of Exception tested by statusOnException() implies that the database is invalid, and the pool should refill itself with fresh Connections.
at com.mchange.v2.c3p0.impl.NewProxyConnection.commit(NewProxyConnection.java:803)
2016-05-16 09:49:20,506 [http-bio-8080-exec-6] WARN [com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool] - A ConnectionTest has failed, reporting that all previously acquired Connections are likely invalid. The pool will be reset.
at com.mchange.v2.c3p0.impl.NewProxyConnection.commit(NewProxyConnection.java:803)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:105)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:105)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:105)

Answer 1

When an Exception occurs on a Connection during a c3p0 Connection test, c3p0 examines the SQL State of the Exception to evaluate whether that means that only the Connection is invalid, or if all Connections in the pool are likely to be invalid given the condition signaled. If the SQL state suggests all Connections are likely to be invalid, c3p0 will reset the pool, close()ing and discarding the Connections it has previously acquired and replacing them with fresh Connections.
You don't need to do anything about this, as long as it is rare or occasional. c3p0 is trying to recover from a database outage as early and as quickly as possible. It is proactively replacing its Connections rather than waiting for each individually, to fail a test and then get replaced.
If this is happening a lot, then there is a problem either with your database or with how Connection tests are getting performed. But that's worth tracking down only if it happens a lot.

Answer 2

it's my OCD,i want fix any warn,i am trying to change the property
this is my old version:
<property name="minPoolSize"><value>5</value>
</property>
<property name="maxPoolSize">
<value>30</value>
</property>
<property name="initialPoolSize">
<value>10</value>
</property>
<property name="maxIdleTime">
<value>60</value>
</property>
<property name="acquireIncrement">
<value>5</value>
</property>
<property name="maxStatements">
<value>0</value>
</property>
<property name="idleConnectionTestPeriod">
<value>60</value>
</property> -->
<property name="acquireRetryAttempts">
<value>30</value>
</property>
<property name="breakAfterAcquireFailure">
<value>true</value>
</property>
<property name="preferredTestQuery" value="SELECT 1"/>
false
new version:
<property name="idleConnectionTestPeriod" value="${c3p0.idleConnectionTestPeriod}" />
<property name="initialPoolSize" value="${c3p0.initialPoolSize}" />
<property name="maxIdleTime" value="${c3p0.maxIdleTime}" />
<property name="maxPoolSize" value="${c3p0.maxPoolSize}" />
<property name="maxStatements" value="${c3p0.maxStatements}" />
<property name="maxStatementsPerConnection" value="${c3p0.maxStatementsPerConnection}" />
<property name="minPoolSize" value="${c3p0.minPoolSize}" />