RE: [JBoss-user] How Can You Manage A Null Connection? Errors

John Moore Tue, 25 Jun 2002 11:00:31 -0700

Title: RE: [JBoss-user] How Can You Manage A Null Connection? Errors

Thanks,

The connection already closed error possibly occurs because we need to
tune idle/gc timeout params better? Just a guess from reading your
responses to other questions in the forums We currently have a very
short timeout, were previously the default was used. Wanted to see if a
quicker cleanup cycle would eliviate the problem. I will try the
blocking if I can find the timeout for blocking param in the code, I
don't remember seeing one earlier but easily could have missed it. We
tested blocking=true without a timeout and it was disasterous.

The code attempts to get a connection. If getConnection() returns null
or con.isClosed() == true, it tries one more time (after calling
con.close(), which may be the cause of the first error in the log) . If
an exception is thrown it's bubbled back up and converted to a nicer
message to the user. The 2nd message is the one that get's trapped,
logged by our app, and displayed to the user.

Two errors from the logs are:

[09:00:35,634,2027] Error cleaning up ManagedConnection:
[09:00:35,635,2027] javax.resource.ResourceException: Unable to rollback
DB connection: java.sql.SQLException: JZ0C0: Connection is already closed.

[09:00:35,644,2027] deleteObject(): Unable to destroy ManagedConnection:
javax.resource.ResourceException: Unable to close DB connection:
java.sql.SQLException: JZ0C0: Connection is already closed.

john moore

-----Original Message-----
From: David Jencks [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, June 25, 2002 8:45 AM
To: [EMAIL PROTECTED]
Subject: Re: [JBoss-user] How Can You Manage A Null Connection? Errors

The first thing is to set Blocking=true. I think you also want
BlockingTimeoutMillis=5000 or you might block forever. (I think this is the
name of this parameter, it's from memory)

I don't remember seeing about the connection already closed error:
what/when is it?

david jencks

On 2002.06.25 11:27:53 -0400 John Moore wrote:
>
>
> We are seeing these "How Can You Manage A Null Connection?" exceptions
> creep
> up randomly when we go to get a connection from a DataSource. I see in
> the
> code where this is thrown but can't figure out how after having the pool
> be
> created (and accessed) successfully I can end up with this exception.
> Unlike the connection already closed that we also get, this one doesn't
> seem
> to go away if you keep trying to grab new connections; it says around
> until
> the jboss is restarted. Stopping and starting the mbean doesn't seem to
> cut it. The error occurs on different pools and at no particular
> interval.
> The database servers may be restarted without our knowledge, but in our
> testing this hasn't been a problem.
>
> We are using JBoss 2.4.3 with embedded Tomcat 3.2.3 and have about 30
> datasources to sybase sqlanywhere 5.5 databases. JBoss is on a Sun Netra
> X1, Solaris 8 (with patches), jdk 1.3.1_02, ulimit -s 2048, ulimit -n
> 1024,
> apache 1.3.24 w/ mod_jk & mod_ssl. Databases are all remote; accessed
> over
> internet connections not LAN or WAN connections. Some are through VPN
> tunnels. All of the datasources initially startup cleanly and we can
> connect
> to each of them without a problem. There are no clues in the log file
> either. Datasources all have the same configuration except the mbean
> name,
> factory name and connection URL in the property attribute.
>
> The application is a group of servlets and JSP's deployed as a war.
>
> 
> <mbean code="org.jboss.resource.ConnectionFactoryLoader"
> name="JCA:service=ConnectionFactoryLoader,name=test">
> <attribute name="FactoryName">test</attribute>
> <attribute
> name="RARDeployerName">JCA:service=RARDeployer</attribute>
> <attribute name="ResourceAdapterName">Minerva JDBC
> LocalTransaction ResourceAdapter</attribute>
> <attribute name="Properties">
> UserName=xxxxxx
> Password=yyyyyy
> Driver=com.sybase.jdbc2.jdbc.SybDriver
>
> ConnectionURL=jdbc:sybase:Tds:192.168.0.15:1498/dbname
> </attribute>
> <attribute
> name="ConnectionManagerFactoryName">MinervaSharedLocalCMFactory</attribute>
> <attribute name="ConnectionManagerProperties">
> MinSize=1
> MaxSize=10
> Blocking=false
> GCEnabled=true
> IdleTimeoutEnabled=true
> InvalidateOnError=false
> TrackLastUsed=true
> GCIntervalMillis=120000
> GCIntervazlMillis=120000
> GCMinIdleMillis=240000
> IdleTimeoutMillis=300000
> MaxIdleTimeoutPercent=0.0
> </attribute>
> <attribute
> name="PrincipalMappingClass">org.jboss.resource.security.ManyToOnePrincipalM
> apping</attribute>
> </mbean>
>
> Has anyone else seen this and is there a solution? I didn't catch
> anything
> in the forums. We're at 30 connections now and am looking to be around
> 100
> soon, but am going to have a big problem if I can't solve this problem.
>
>
> Thanks,
> John Moore
>
> Principal Decision Systems International
> 625 The City Drive
> Suite 190
> Orange, CA 92868
> 800-850-7374
>
>
>
> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
> <HTML>
> <HEAD>
> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
> <META NAME="Generator" CONTENT="MS Exchange Server version 5.5.2653.12">
> <TITLE>How Can You Manage A Null Connection? Errors</TITLE>
> </HEAD>
> <BODY>
> 
> 
>
> We are seeing these "How Can You Manage A Null
> Connection?" exceptions creep up randomly when we go to get a
> connection from a DataSource. I see in the code where this is thrown but
> can't figure out how after having the pool be created (and accessed)
> successfully I can end up with this exception.   Unlike the
> connection already closed that we also get, this one doesn't seem to go
> away if you keep trying to grab new connections; it says around until the
> jboss is restarted.   Stopping and starting the mbean doesn't
> seem to cut it.   The error occurs on different pools and at no
> particular interval.   The database servers may be restarted
> without our knowledge, but in our testing this hasn't been a
> problem.
>
> We are using JBoss 2.4.3 with embedded Tomcat 3.2.3 and
> have about 30 datasources to sybase sqlanywhere 5.5 databases. 
> JBoss is on a Sun Netra X1, Solaris 8 (with patches),  jdk 1.3.1_02,
> ulimit -s 2048, ulimit -n 1024, apache 1.3.24 w/ mod_jk &
> mod_ssl.   Databases are all remote; accessed over internet
> connections not LAN or WAN connections.  Some are through VPN
> tunnels. All of the datasources initially startup cleanly and we can
> connect to each of them without a problem.   There are no clues
> in the log file either.  Datasources all have the same configuration
> except the mbean name, factory name and connection URL in the property
> attribute.  
>
> The application is a group of servlets and JSP's deployed
> as a war.
> 
>
>         
>         <mbean
> code="org.jboss.resource.ConnectionFactoryLoader"
> name="JCA:service=ConnectionFactoryLoader,name=test">
>            
> <attribute name="FactoryName">test</attribute>
>            
> <attribute name="RARDeployerName">JCA:service=RARDeployer</attribute>
>            
> <attribute name="ResourceAdapterName">Minerva JDBC
> LocalTransaction ResourceAdapter</attribute>
>            
> <attribute name="Properties">
>

> UserName=xxxxxx
>

> Password=yyyyyy
>

> Driver=com.sybase.jdbc2.jdbc.SybDriver
>

> ConnectionURL=jdbc:sybase:Tds:192.168.0.15:1498/dbname
>            
> </attribute>
>            
> <attribute name="ConnectionManagerFactoryName">MinervaSharedLocalCMFactory</attribute>
>            
> <attribute name="ConnectionManagerProperties">
>

> MinSize=1
>

> MaxSize=10
>

> Blocking=false
>

> GCEnabled=true
>

> IdleTimeoutEnabled=true
>

> InvalidateOnError=false
>

> TrackLastUsed=true
>

> GCIntervalMillis=120000
>

> GCIntervazlMillis=120000
>

> GCMinIdleMillis=240000
>

> IdleTimeoutMillis=300000
>

> MaxIdleTimeoutPercent=0.0
>            
> </attribute>
>            
> <attribute name="PrincipalMappingClass">org.jboss.resource.security.ManyToOnePrincipalMapping</attribute>

>        
> </mbean>
> 
>
> Has anyone else seen this and is there a solution? I
> didn't catch anything in the forums.  We're at 30 connections now
> and am looking to be around 100 soon, but am going to have a big problem
> if I can't solve this problem.    
>
> Thanks,
> John Moore
> 
>
> Principal Decision Systems International
> 625 The City Drive
> Suite 190
> Orange, CA 92868
> 800-850-7374
> 
> 
>
> </BODY>
> </HTML>
>

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