The following bug has been logged online:

Bug reference: 2060
Logged by: Manideep Kalisetty
Email address: mani7deep (AT) yahoo (DOT) com
PostgreSQL version: 7.2.2
Operating system: Windows and Linux
Description: Issue with Data base connection
Details:

I am using postgresql-8.1dev-402.jdbc3.jar JDBC driver and websphere
application server. Even though I am successfully closing connections, the
error message I am receivng is "Backend start-up failed: FATAL 1: Sorry,
too many clients already". Please refer to the Exception report below:


[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R
org.postgresql.util.PSQLException: Backend start-up failed: FATAL 1: Sorry,
too many clients already
..
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
org.postgresql.core.v2.ConnectionFactoryImpl.readS tartupMessages(ConnectionF
actoryImpl.java(Compiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
org.postgresql.core.v2.ConnectionFactoryImpl.openC onnectionImpl(ConnectionFa
ctoryImpl.java(Compiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
org.postgresql.core.ConnectionFactory.openConnecti on(ConnectionFactory.java(
Compiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
org.postgresql.jdbc2.AbstractJdbc2Connection.<init >(AbstractJdbc2Connection.
java(Compiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
org.postgresql.jdbc3.AbstractJdbc3Connection.<init >(AbstractJdbc3Connection.
java(Inlined Compiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
org.postgresql.jdbc3.Jdbc3Connection.<init>(Jdbc3C onnection.java(Inlined
Compiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
org.postgresql.Driver.makeConnection(Driver.java(I nlined Compiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
org.postgresql.Driver.connect(Driver.java(Compiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
java.sql.DriverManager.getConnection(DriverManager .java(Compiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
java.sql.DriverManager.getConnection(DriverManager .java(Inlined Compiled
Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
kanbay.dao.DBAccess.getConnection(DBAccess.java(Co mpiled Code))
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
kanbay.dao.ContributorsDAO.getContributorsOfTheMon th(ContributorsDAO.java:11
9)
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
kanbay.com.GenericServlet.doPost(GenericServlet.ja va:124)
[11/21/05 10:28:54:836 IST] 50b9631a SystemErr R at
kanbay.com.GenericServlet.doGet(GenericServlet.jav a:48)
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
javax.servlet.http.HttpServlet.service(HttpServlet .java:740)
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
javax.servlet.http.HttpServlet.service(HttpServlet .java(Compiled Code))
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.servlet.StrictServletInsta nce.doService(StrictServle
tInstance.java(Compiled Code))
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.servlet.StrictLifecycleSer vlet._service(StrictLifecy
cleServlet.java(Compiled Code))
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.servlet.IdleServletState.s ervice(StrictLifecycleServ
let.java:313)
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.servlet.StrictLifecycleSer vlet.service(StrictLifecyc
leServlet.java(Inlined Compiled Code))
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.servlet.ServletInstance.se rvice(ServletInstance.java
(Compiled Code))
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.servlet.ValidServletRefere nceState.dispatch(ValidSer
vletReferenceState.java(Compiled Code))
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.servlet.ServletInstanceRef erence.dispatch(ServletIns
tanceReference.java(Inlined Compiled Code))
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.webapp.WebAppRequestDispat cher.handleWebAppDispatch(
WebAppRequestDispatcher.java(Compiled Code))
[11/21/05 10:28:54:846 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.webapp.WebAppRequestDispat cher.dispatch(WebAppReques
tDispatcher.java(Compiled Code))
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.webapp.WebAppRequestDispat cher.forward(WebAppRequest
Dispatcher.java:200)
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.srt.WebAppInvoker.doForwar d(WebAppInvoker.java:119)
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.srt.WebAppInvoker.handleIn vocationHook(WebAppInvoker
..java:276)
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.cache.invocation.CachedInv ocation.handleInvocation(C
achedInvocation.java:71)
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.cache.invocation.Cacheable InvocationContext.invoke(C
acheableInvocationContext.java:116)
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.srp.ServletRequestProcesso r.dispatchByURI(ServletReq
uestProcessor.java:186)
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.oselistener.OSEListenerDis patcher.service(OSEListene
r.java:334)
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.webcontainer.http.HttpConnection.handle Request(HttpConnection.jav
a:56)
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.http.HttpConnection.readAndHandleReques t(HttpConnection.java:618)

[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.http.HttpConnection.run(HttpConnection. java:443)
[11/21/05 10:28:54:867 IST] 50b9631a SystemErr R at
com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.j ava:672)

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On Mon, 21 Nov 2005, Manideep Kalisetty wrote:

Well, something is leaving connections open. Checking the results of
SELECT * FROM pg_stat_activity; will tell you what database and username
they are connected to which may help. While this code doesn't appear to
be using a connection pool, perhaps you have another application that is
using a pool that is configured to open too many connections? Still, the
most likely cause is a coding error failing to close connections.

Kris Jurka

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kalisetty manideep wrote:
I have no reason to believe that and you certainly haven't shown that.

All this shows is the Connection being opened, not closed.

I've implemented an idea I got from rupa in #postgresql a while ago
about a way of logging leaked connections. I've added some code to the
Connection's finalize() method that prints some logging information if
the Connection was not closed. This is enabled by using the new
logUnclosedConnections URL parameter.

See the attached code for an example. I've put up a new jar that
contains this here: http://www.ejurka.com/pgsql/jars/km

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import java.sql.*;

public class OpenConn {

public static void main(String args[]) throws Exception {
Class.forName("org.postgresql.Driver");
leakConnection();
System.gc();
}

private static void leakConnection() throws Exception {
Connection conn = DriverManager.getConnection("jdbcostgresql://localhost:5810/jurka?logUnclosedConnections=true","jurka","");
}

}


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