Hi
My application uses hibernate for persistence and c3p0 as connection pool. The following is the configuration I have:
<property name="hibernate.c3p0.min_size">6</property>
<property name="hibernate.c3p0.max_size">35</property>
<property name="nontransaction.connection">15</property>
<property name="hibernate.connection.autocommit">true</property>
My connection pool size is low and I am not working under high load. I see the following exception:
org.hibernate.exception.GenericJDBCException: Cannot open connection
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:426)
at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:144)
at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:57)
at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1326)
at com.adventnet.management.transaction.TransactionAPI.beginHbnTxn(TransactionAPI.java:923)
at com.adventnet.management.transaction.TransactionAPI.beginTxn(TransactionAPI.java:856)
at com.adventnet.management.transaction.TransactionAPI.begin(TransactionAPI.java:314)
at com.adventnet.nms.store.relational.RelationalObject.beginTxn(RelationalObject.java:2298)
at com.adventnet.nms.store.relational.RelationalObject.init(RelationalObject.java:208)
at com.adventnet.nms.store.relational.RelationalPolicyObject.init(RelationalPolicyObject.java:39)
at com.adventnet.nms.store.relational.CommonPolicyToRelational.initForClass(CommonPolicyToRelational.java:145)
at com.adventnet.nms.store.relational.CommonPolicyToRelational.<init>(CommonPolicyToRelational.java:76)
at com.adventnet.management.policydb.CommonPolicyAPI.setPersistenceAPI(CommonPolicyAPI.java:63)
at com.adventnet.management.policydb.CommonPolicyAPI.<init>(CommonPolicyAPI.java:43)
at com.adventnet.management.policydb.NmsPolicyMgr.initialize(NmsPolicyMgr.java:115)
at com.adventnet.management.policydb.NmsPolicyMgr.callMain(NmsPolicyMgr.java:99)
at com.adventnet.nms.util.RunProcessSmall.runCommand(RunProcessSmall.java:97)
at com.adventnet.nms.util.RunCmd.run(RunCmd.java:100)
Caused by: java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:65)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:527)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
at org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:56)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:423)
... 18 more
Caused by: com.mchange.v2.resourcepool.TimeoutException: A client timed out while waiting to acquire a resource from com.mchange.v2.resourcepool.BasicResourcePool@869113 -- timeout at awaitAvailable()
at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1317)
at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
When I did some debugging from my side, I figured out that the number of non-transaction connections taken from the connection pool are 10 and non transaction connections are 3. At this point this issue occurs and also if I increase the connection pool size to 45, this issue no longer occurs.
What could be the reason? Is there a way to enable some fine level of debugging in c3p0 ( using log4j).
My application uses hibernate for persistence and c3p0 as connection pool. The following is the configuration I have:
<property name="hibernate.c3p0.min_size">6</property>
<property name="hibernate.c3p0.max_size">35</property>
<property name="nontransaction.connection">15</property>
<property name="hibernate.connection.autocommit">true</property>
My connection pool size is low and I am not working under high load. I see the following exception:
org.hibernate.exception.GenericJDBCException: Cannot open connection
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:426)
at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:144)
at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:57)
at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1326)
at com.adventnet.management.transaction.TransactionAPI.beginHbnTxn(TransactionAPI.java:923)
at com.adventnet.management.transaction.TransactionAPI.beginTxn(TransactionAPI.java:856)
at com.adventnet.management.transaction.TransactionAPI.begin(TransactionAPI.java:314)
at com.adventnet.nms.store.relational.RelationalObject.beginTxn(RelationalObject.java:2298)
at com.adventnet.nms.store.relational.RelationalObject.init(RelationalObject.java:208)
at com.adventnet.nms.store.relational.RelationalPolicyObject.init(RelationalPolicyObject.java:39)
at com.adventnet.nms.store.relational.CommonPolicyToRelational.initForClass(CommonPolicyToRelational.java:145)
at com.adventnet.nms.store.relational.CommonPolicyToRelational.<init>(CommonPolicyToRelational.java:76)
at com.adventnet.management.policydb.CommonPolicyAPI.setPersistenceAPI(CommonPolicyAPI.java:63)
at com.adventnet.management.policydb.CommonPolicyAPI.<init>(CommonPolicyAPI.java:43)
at com.adventnet.management.policydb.NmsPolicyMgr.initialize(NmsPolicyMgr.java:115)
at com.adventnet.management.policydb.NmsPolicyMgr.callMain(NmsPolicyMgr.java:99)
at com.adventnet.nms.util.RunProcessSmall.runCommand(RunProcessSmall.java:97)
at com.adventnet.nms.util.RunCmd.run(RunCmd.java:100)
Caused by: java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:65)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:527)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
at org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:56)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:423)
... 18 more
Caused by: com.mchange.v2.resourcepool.TimeoutException: A client timed out while waiting to acquire a resource from com.mchange.v2.resourcepool.BasicResourcePool@869113 -- timeout at awaitAvailable()
at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1317)
at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
When I did some debugging from my side, I figured out that the number of non-transaction connections taken from the connection pool are 10 and non transaction connections are 3. At this point this issue occurs and also if I increase the connection pool size to 45, this issue no longer occurs.
What could be the reason? Is there a way to enable some fine level of debugging in c3p0 ( using log4j).