Diagnosis of C3P0

Databaseconnectionleak connection leak Diagnostic method using C3P0 connection pool Enable C3P0 connection return timeout setting

In the C3p0 property configuration file (0.datasource.config), set the following properties:

Debugunreturnedconnectionstacktraces=true
unreturnedconnectiontimeout=1200

Where: Debugunreturnedconnectionstacktraces is a switch, enabled, for each database connection from the connection pool, if not returned for a period of time, C3P0 will force the connection to close, and will get the stack Trace, which is displayed in a way that throws an exception. How long the unreturnedconnectiontimeout setting times out, in seconds.

Assuming that a connection leak is suspected in the system, you can enable this feature to evaluate the maximum time required for all page execution to complete, such as 20 minutes, and then set Unreturnedconnectiontimeout to a slightly larger time. set the log output of c3p0

In order to see the exception information thrown by C3P0, you also need to set the log property of C3P0. The easiest way to do this is to have C3P0 use the JDK standard log API so that no additional jars need to be loaded. Set startup parameters When starting the JVM: Dcom.mchange.v2.log.mlog=com.mchange.v2.log.jdk14logging.jdk14mlog

In Tomcat, you can modify the catalina.sh and set the java_opts variable to contain the above content.

You can do one test: Set the C3p0 property Debugunreturnedconnectionstacktraces=true,unreturnedconnectiontimeout=1, and then access a page that runs longer than 1 seconds. This way, you will see a message in the Output window of Tomcat:

Info: Logging the stack trace by which the overdue resource is checked-out.
	Java.lang.Exception:DEBUG only:overdue resource Check-out stack trace. At Com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource (Basicresourcepool.java:<span class=) Hl-number ">506</span>" at Com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection ( C3p0pooledconnectionpool.java:<span class= "Hl-number" >525</span>) at Com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection (Abstractpoolbackeddatasource.java:<span class= "Hl-number" >128</span>) at Aurora.database.service.SqlServiceContext.initConnection ( Sqlservicecontext.java:<span class= "Hl-number" >168</span>) at Aurora.database.service.BusinessModelService.prepareForRun (Businessmodelservice.java:<span class= "Hl-number" >112</span>) at Aurora.database.service.BusinessModelService.query (Businessmodelservice.java:<span
	class= "Hl-number" >188</span>)At Aurora.database.actions.ModelQuery.doQuery (modelquery.java:<span class= "Hl-number" >53</span>) at Aurora.database.actions.AbstractQueryAction.query (Abstractqueryaction.java:<span class= "Hl-number" >104 </span>) at Aurora.database.actions.AbstractQueryAction.run (Abstractqueryaction.java:<span class=) Hl-number ">115</span>" at Uncertain.proc.ProcedureRunner.run (Procedurerunner.java:<span class=) Hl-number ">253</span>" at Uncertain.proc.ProcedureRunner.run (Procedurerunner.java:<span class=) Hl-number ">290</span>" at Uncertain.proc.Procedure.run (Procedure.java:<span class= "Hl-number" >94 </span>) at Uncertain.proc.ProcedureRunner.run (Procedurerunner.java:<span class= "Hl-number" >247</ span>) at Aurora.application.features.AbstractProcedureInvoker.runProcedure (Abstractprocedureinvoker.java: <span class= "Hl-number" >40</span>) at Aurora.application.features.InitProcedureInvoker.doInvoke ( initproceduReinvoker.java:<span class= "Hl-number" >33</span>) at Aurora.application.features.InitProcedureInvoker.onCreateModel (Initprocedureinvoker.java:<span class=) Hl-number ">37</span>" at Sun.reflect.NativeMethodAccessorImpl.invoke0 (Native method) at Sun.reflect.NativeMethodAccessorImpl.invoke (Nativemethodaccessorimpl.java:<span class= "Hl-number" >39</ span>) at Sun.reflect.DelegatingMethodAccessorImpl.invoke (Delegatingmethodaccessorimpl.java:<span class= " Hl-number ">25</span>" at Java.lang.reflect.Method.invoke (Method.java:<span class= "Hl-number" >597 </span>) at Uncertain.proc.ReflectionMethodHandle.handleEvent (Reflectionmethodhandle.java:<span class=) Hl-number ">93</span>" at Uncertain.proc.ReflectionMethodHandle.handleEvent (Reflectionmethodhandle.java: <span class= "Hl-number" >50</span>) at Uncertain.event.Configuration.fireEventInternal ( Configuration.java:<span class= "Hl-number" >403</span>) at Uncertain.event.Configuration.fireEvent (Configuration.java:<span class= "Hl-number" >341</span>) at Uncertain.proc.ProcedureRunner.fireEvent (Procedurerunner.java:<span class= "Hl-number" >312</span>) at Uncertain.proc.Action.run (Action.java:<span class= "Hl-number" >171</span>) at Uncertain.proc.ProcedureRunner.run (Procedurerunner.java:<span class= "Hl-number" >253</span>) at Uncertain.proc.ProcedureRunner.run (Procedurerunner.java:<span class= "Hl-number" >290</span>) at Uncertain.proc.Procedure.run (Procedure.java:<span class= "Hl-number" >94</span>) at Uncertain.proc.Switch.run (Switch.java:<span class= "Hl-number" >87</span>) at Uncertain.proc.ProcedureRunner.run (Procedurerunner.java:<span class= "Hl-number" >253</span>) at Uncertain.proc.ProcedureRunner.run (Procedurerunner.java:<span class= "Hl-number" >290</span>) at Uncertain.proc.Procedure.run (Procedure.java:<span class= "Hl-numbeR ">94</span>" at Uncertain.proc.ProcedureRunner.run (Procedurerunner.java:<span class= "Hl-number" > 247</span>) at Aurora.service.ServiceInstance.invoke (Serviceinstance.java:<span class= "Hl-number" >124 </span>) at Aurora.service.http.AbstractFacadeServlet.service (Abstractfacadeservlet.java:<span class=) Hl-number ">116</span>" at Javax.servlet.http.HttpServlet.service (Httpservlet.java:<span class=) Hl-number ">722</span>" at Org.apache.catalina.core.ApplicationFilterChain.internalDoFilter ( Applicationfilterchain.java:<span class= "Hl-number" >306</span>) at Org.apache.catalina.core.ApplicationFilterChain.doFilter (Applicationfilterchain.java:<span class= "Hl-number" >210</span>) at Org.apache.catalina.core.StandardWrapperValve.invoke (Standardwrappervalve.java:<span class= "Hl-number" >240</span>) at Org.apache.catalina.core.StandardContextValve.invoke ( Standardcontextvalve.java:<span class= "Hl-number">161</span>" at Org.apache.catalina.core.StandardHostValve.invoke (Standardhostvalve.java:<span class = "Hl-number" >164</span>) at Org.apache.catalina.valves.ErrorReportValve.invoke (Errorreportvalve.java: <span class= "Hl-number" >100</span>) at Org.apache.catalina.valves.AccessLogValve.invoke ( Accesslogvalve.java:<span class= "Hl-number" >541</span>) at Org.apache.catalina.core.StandardEngineValve.invoke (Standardenginevalve.java:<span class= "Hl-number" >118 </span>) at Org.apache.catalina.connector.CoyoteAdapter.service (Coyoteadapter.java:<span class=) Hl-number ">383</span>" at Org.apache.coyote.http11.Http11Processor.process (http11processor.java:< Span class= "Hl-number" >243</span>) at org.apache.coyote.http11.http11protocol$ Http11connectionhandler.process (Http11protocol.java:<span class= "Hl-number" >188</span>) at Org.apache.coyote.http11.http11protocol$http11connectionhandler.process (Http11protocOl.java:<span class= "Hl-number" >166</span>) at org.apache.tomcat.util.net.jioendpoint$ Socketprocessor.run (Jioendpoint.java:<span class= "Hl-number" >288</span>) at Java.util.concurrent.threadpoolexecutor$worker.runtask (Threadpoolexecutor.java:<span class= "Hl-number" > 886</span>) at Java.util.concurrent.threadpoolexecutor$worker.run (Threadpoolexecutor.java:<span class= " Hl-number ">908</span>" at Java.lang.Thread.run (Thread.java:<span class= "Hl-number" >680</span
 >)

This is the information that c3p0 discovered after 1 seconds of connection, forced to close the connection, and, as you can see from stack trace, Getting the connection is happening in Aurora.database.service.BusinessModelService.query, which is invoking BM's query.

Since the page does need to use a connection for more than 1 seconds, the connection being used is forced to close, and you will see this information:

<span class= "Hl-number" >011</span>-<span class= "Hl-number" >6</span>-<span "class=" Hl-number ">22</span> <span class=" Hl-number ">13</span>:<span class=" Hl-number ">24</" Span>:<span class= "Hl-number" >15</span> com.mchange.v2.c3p0.impl.NewPooledConnection handlethrowable
Warning: [C3P0] A pooledconnection that has already signalled a Connection the error is still in use!

Subsequent SQL operations that use this connection will find that the connection is closed and a similar exception will be thrown:

<span class= "Hl-number" >2011</span>-<span class= "Hl-number" >6</span>-<span "class=" Hl-number ">22</span> <span class=" Hl-number ">13</span>:<span class=" Hl-number ">24</" Span>:<span class= "Hl-number" >15</span> com.mchange.v2.c3p0.impl.NewPooledConnection Handlethrowable warning: [C3P0] Another error has occurred [java.sql.SQLException: Closed connection] which'll not is reported to list
eners! Java.sql.SQLException: Closed connection at oracle.jdbc.dbaccess.DBError.throwSqlException (Dberror.java:<span class= " Hl-number ">134</span>" at Oracle.jdbc.dbaccess.DBError.throwSqlException (Dberror.java:<span class=) Hl-number ">179</span>" at Oracle.jdbc.dbaccess.DBError.throwSqlException (Dberror.java:<span class=) Hl-number ">269</span>" at Oracle.jdbc.driver.OracleConnection.rollback (Oracleconnection.java:<span class= "Hl-number" >1439</span>) at Com.mchange.v2.c3p0.impl.NewProxyConnection.rollback (NewproxYconnection.java:<span class= "Hl-number" >855</span>) at Aurora.transaction.UserTransactionImpl.rollback (Usertransactionimpl.java:<span class= "Hl-number" >58</ span>) at Aurora.service.http.AbstractFacadeServlet.service (Abstractfacadeservlet.java:<span class= " Hl-number ">141</span>" at Javax.servlet.http.HttpServlet.service (Httpservlet.java:<span class=) Hl-number ">722</span>" at Org.apache.catalina.core.ApplicationFilterChain.internalDoFilter ( Applicationfilterchain.java:<span class= "Hl-number" >306</span>) at Org.apache.catalina.core.ApplicationFilterChain.doFilter (Applicationfilterchain.java:<span class= "Hl-number" >210</span>) at Org.apache.catalina.core.StandardWrapperValve.invoke (Standardwrappervalve.java:<span class= "Hl-number" >240</span>) at Org.apache.catalina.core.StandardContextValve.invoke ( Standardcontextvalve.java:<span class= "Hl-number" >161</span>) at ORG.APACHE.CATALINA.CORE.STandardhostvalve.invoke (Standardhostvalve.java:<span class= "Hl-number" >164</span>) at Org.apache.catalina.valves.ErrorReportValve.invoke (Errorreportvalve.java:<span class= "Hl-number" >100</ span>) at Org.apache.catalina.valves.AccessLogValve.invoke (Accesslogvalve.java:<span class= "Hl-number" > 541</span>) at Org.apache.catalina.core.StandardEngineValve.invoke (Standardenginevalve.java:<span class= "Hl-number" >118</span>) at Org.apache.catalina.connector.CoyoteAdapter.service (coyoteadapter.java:< Span class= "Hl-number" >383</span>) at Org.apache.coyote.http11.Http11Processor.process ( Http11processor.java:<span class= "Hl-number" >243</span>) at org.apache.coyote.http11.http11protocol$ Http11connectionhandler.process (Http11protocol.java:<span class= "Hl-number" >188</span>) at Org.apache.coyote.http11.http11protocol$http11connectionhandler.process (Http11protocol.java:<span class=) Hl-number ">166</span>) at Org.apache.tomcat.util.net.jioendpoint$socketprocessor.run (jioendpoint.java:<span class= "Hl-number" > 288</span>) at Java.util.concurrent.threadpoolexecutor$worker.runtask (Threadpoolexecutor.java:<span class= "Hl-number" >886</span>) at Java.util.concurrent.threadpoolexecutor$worker.run ( Threadpoolexecutor.java:<span class= "Hl-number" >908</span>) at Java.lang.Thread.run (thread.java:< Span class= "Hl-number" >680</span>)