Thread: Query Executor Problem
Hi,
Our web based application which is using postgresql version 7.1.3 is
showing an error as follows.
java.lang.NullPointerException
at org.postgresql.core.QueryExecutor.execute(QueryExecutor.java:61)
at org.postgresql.Connection.ExecSQL(Connection.java:398)
at org.postgresql.jdbc2.Statement.execute(Statement.java:130
at org.postgresql.jdbc2.Statement.executeQuery(Statement.java:54)
at
com.ebusinessoft.gen.db.DatabaseUtilities.getQueryResults(DatabaseUtilities.java:71)
at com.ebusinessoft.ifos.rsmt.gentrip.doGet(gentrip.java:124)
at com.ebusinessoft.ifos.rsmt.gentrip.doPost(gentrip.java:448)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:404)
at org.apache.tomcat.core.Handler.service(Handler.java:286)
at
org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
at
org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:797)
at
org.apache.tomcat.core.ContextManager.service(ContextManager.java:743)
at
org.apache.tomcat.service.connector.Ajp12ConnectionHandler.processConnection(Ajp12ConnectionHandler.java:166)
at
org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416)
at
org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498)
at java.lang.Thread.run(Thread.java:484)
This type of message occurs at random and we could not assess the reason for
this. We greatly appreciate your help on this.
Thanks
Support
support@ebusinessoft.com
In our case we had to make sure to discard/close/clean the connection ourself EVERYWHERE. We realized that in some circonstances our application server did not release and close properly the connection from our pool. Usually it called connection.clearWarnings(), connection.setAutoCommit(true); and closes the connection whenever there was an exception. Strange things happen when the GarbageCollector/Finalizer runs and tries to call the method org.postgresql.Connection.finalize() which calls org.postgresql.Connection.close which execute pg_stream=null; And it is this variable pg_stream which is null in the QueryExecutor at line 61. The finalizer seems to disrupt internal stuff that it should not have (database socket?), anyway you should not rely on the finalize method. From what I remember is that we make sure WE close the connection and not the gargage collector. The Connection.close instruction should be the last instruction you execute on a connection. Good luck. Daniel > -----Original Message----- > From: Email User [mailto:support@ebusinessoft.com] > Sent: November 6, 2002 1:35 AM > To: daniel.germain@gipsynet.com > Cc: pgsql-jdbc@postgresql.org > Subject: Query Executor Problem > > > Hi, > Our web based application which is using postgresql version 7.1.3 is > showing an error as follows. > > java.lang.NullPointerException > at > org.postgresql.core.QueryExecutor.execute(QueryExecutor.java:61) > at org.postgresql.Connection.ExecSQL(Connection.java:398) > at org.postgresql.jdbc2.Statement.execute(Statement.java:130 > at org.postgresql.jdbc2.Statement.executeQuery(Statement.java:54) > at > com.ebusinessoft.gen.db.DatabaseUtilities.getQueryResults(Database > Utilities.java:71) > at com.ebusinessoft.ifos.rsmt.gentrip.doGet(gentrip.java:124) > at com.ebusinessoft.ifos.rsmt.gentrip.doPost(gentrip.java:448) > at javax.servlet.http.HttpServlet.service(HttpServlet.java:760) > at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) > at > org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:404) > at org.apache.tomcat.core.Handler.service(Handler.java:286) > at > org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) > at > org.apache.tomcat.core.ContextManager.internalService(ContextManag > er.java:797) > at > org.apache.tomcat.core.ContextManager.service(ContextManager.java:743) > at > org.apache.tomcat.service.connector.Ajp12ConnectionHandler.process > Connection(Ajp12ConnectionHandler.java:166) > at > org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) > at > org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) > at java.lang.Thread.run(Thread.java:484) > > > This type of message occurs at random and we could not assess the > reason for > this. We greatly appreciate your help on this. > > Thanks > Support > support@ebusinessoft.com >
I had this error as well, and tracked it down to my trying to use a
Connnection object that had been closed.
-----Original Message-----
From: pgsql-jdbc-owner@postgresql.org
[mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of Email User
Sent: Wednesday, November 06, 2002 12:35 AM
To: daniel.germain@gipsynet.com
Cc: pgsql-jdbc@postgresql.org
Subject: [JDBC] Query Executor Problem
Hi,
Our web based application which is using postgresql version 7.1.3 is
showing an error as follows.
java.lang.NullPointerException
at
org.postgresql.core.QueryExecutor.execute(QueryExecutor.java:61)
at org.postgresql.Connection.ExecSQL(Connection.java:398)
at org.postgresql.jdbc2.Statement.execute(Statement.java:130
at
org.postgresql.jdbc2.Statement.executeQuery(Statement.java:54)
at
com.ebusinessoft.gen.db.DatabaseUtilities.getQueryResults(DatabaseUtilit
ies.java:71)
at com.ebusinessoft.ifos.rsmt.gentrip.doGet(gentrip.java:124)
at com.ebusinessoft.ifos.rsmt.gentrip.doPost(gentrip.java:448)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:404)
at org.apache.tomcat.core.Handler.service(Handler.java:286)
at
org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
at
org.apache.tomcat.core.ContextManager.internalService(ContextManager.jav
a:797)
at
org.apache.tomcat.core.ContextManager.service(ContextManager.java:743)
at
org.apache.tomcat.service.connector.Ajp12ConnectionHandler.processConnec
tion(Ajp12ConnectionHandler.java:166)
at
org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416
)
at
org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:49
8)
at java.lang.Thread.run(Thread.java:484)
This type of message occurs at random and we could not assess the reason
for
this. We greatly appreciate your help on this.
Thanks
Support
support@ebusinessoft.com
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TIP 4: Don't 'kill -9' the postmaster
Me too. I had the some problem. And couldn't figure out why when I was using tomcat. The point is that the docs at jakarta.apache.orgdo not really explain the use of the parameters for me. If you use some database as a datasource, the connectionswill go back into the pool, for a while and get recycled, so you should never call connection.close() when youretrieve a database using a DataSource object from a jndi tree. Just don't forget to set the <maxIdle> parameter to aacceptable high value (higher that the <maxActive> parameter which is the number of connections that are actually openedby tomcat to process any request). This way the connections will get pooled and recycled correctly. >I had this error as well, and tracked it down to my trying to use a >Connnection object that had been closed. > >-----Original Message----- >From: pgsql-jdbc-owner@postgresql.org >[mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of Email User >Sent: Wednesday, November 06, 2002 12:35 AM >To: daniel.germain@gipsynet.com >Cc: pgsql-jdbc@postgresql.org >Subject: [JDBC] Query Executor Problem >Hi, >Our web based application which is using postgresql version 7.1.3 >java.lang.NullPointerException > at >org.postgresql.core.QueryExecutor.execute(QueryExecutor.java:61)