FAQ - READ THIS SECOND

[adrian.brock]

DO NOT POST QUESTIONS ON THIS TOPIC - they will be deleted.

Example deployments can be found in the jboss distribution in

docs/examples/jca

The FAQ has moved to here: http://www.jboss.org/wiki/Wiki.jsp?page=FAQJBossJCA

[adrian.brock]

Question:

Is it possible to shutdown the database and restart it?
Will JBoss complain about stale connections?

Answer;

You can configure the following in your -ds.xml

<check-valid-connection-sql>some cheap sql statement</check-valid-connection-sql>
e.g. for Oracle "select 1 from dual"

JBoss will run the SQL statement before handing out the connection from the pool.
If the SQL fails, the connection will be destroyed/closed and new ones will be created.

Regards,
Adrian

[gshifrin]

Thank you for reply.

This can easily reproduce with a simple servlet handling HttpSession.
like this:

public void doGet(HttpServletRequest request, HttpServletResponse response)
 throws ServletException, IOException {

 HttpSession session = request.getSession();
 Integer value = (Integer)session.getAttribute("COUNT");
 if (value == null) {
 value = new Integer(0);
 }
 session.setAttribute("COUNT", new Integer(value.intValue() + 1));

 /* building html */
}

and stress the servlet using JMeter(100threads or more...).
mod_jk2 is not necessary requirement for this problem.

I found this problem only with 4.0.0.
With 3.2.6, this didn't occur.

This is not log4j issue. The duplicate commit message is found only for the TX which ends up with the error log.

[adrian.brock]

jboss-3.2.5 does not support context level overrides. jboss-3.2.6 supports a WEB-INF/context.xml descriptor that allows one to customize a war context. The custom valve would be added by including a myapp-web.war/WEB-INF/context.xml with:

<Context>
 <Valve className="org.apache.catalina.authenticator.FormAuthenticator"
 disableProxyCaching="false" />
</Context>

With this the headers for the jmx-console secured using form auth look like:

http://localhost:8080/jmx-console/

GET /jmx-console/ HTTP/1.1
Host: localhost:8080
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.3) Gecko/20040910
Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Cookie: JSESSIONID=73BBE64CC7EE140B8BE9564A3674B5C2

HTTP/1.x 200 OK
Set-Cookie: JSESSIONID=544A25A77D9EEBB2AD92719D5B63262F; Path=/jmx-console
Etag: W/"711-1098230852000"
Last-Modified: Wed, 20 Oct 2004 00:07:32 GMT
Content-Type: text/html
Content-Length: 711
Date: Wed, 20 Oct 2004 00:24:10 GMT
Server: Apache-Coyote/1.1
----------------------------------------------------------

Without this or with the disableProxyCaching=true there are Pragma: No-cache and Cache-Control: no-cache headers in the replies:

http://localhost:8080/jmx-console/

GET /jmx-console/ HTTP/1.1
Host: localhost:8080
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.3) Gecko/20040910
Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Cookie: JSESSIONID=544A25A77D9EEBB2AD92719D5B63262F

HTTP/1.x 200 OK
Pragma: No-cache
Cache-Control: no-cache
Expires: Wed, 31 Dec 1969 16:00:00 PST
Etag: W/"711-1098230852000"
Last-Modified: Wed, 20 Oct 2004 00:07:32 GMT
Content-Type: text/html
Content-Length: 711
Date: Wed, 20 Oct 2004 00:27:13 GMT
Server: Apache-Coyote/1.1
----------------------------------------------------------

[adrian.brock]

Question:

How do I deploy my resource adapter

Answer:

Take your standard rar deployment (either as a standalone deployment or
part of another deployment like an ear) and place it in deploy.
You then need a -ds.xml file, examples can be found in docs/examples/jca
or the jms resource adapater deployment deploy/jms/jms-ds.xml

The rar acts as a template for the connection factory deployment in the ds.xml

NOTE: It is important for non-jdbc deployments that the
adapter-display-name matches the display-name from the ra.xml inside
the rar.
But in jboss4, it uses rar-name and connection-definition NOT adapter-display-name.
http://www.jboss.org/wiki/Wiki.jsp?page=ConfigConnectionFactory

The full detail of what goes in the -ds.xml can be found in
docs/dtd/jboss-ds_1_0.dtd or the admin docs.

NOTE: If you are deploying a datasource, you will also need to put the
jdbc driver in server/[config]/lib

Regards,
Adrian

[adrian.brock]

Question:

I get messages like the following, what does it mean:

14:58:16,555 WARN [WrappedConnection] Closing a statement you left open, please do your own housekeeping

Answer:
It means you are not closing your connections to return them to the pool.
To avoid connection leaks you should have code like the following:

Connection connection = dataSource.getConnection();
try
{
// DO WORK
}
finally
{
 try
 {
 connection.close();
 }
 catch (Throwable ignored)
 {
 }
}

For jdbc you should do the same thing for Statements and ResultSets.
Normally Statements are closed when the Connection is closed, but connection
pooling means the close does not happen.
Similarly, if you have prepared statements in a cache, ResultSets need to be
closed.

Regards,
Adrian

[adrian.brock]

Question:

I suspect I have a leak, can JBoss tell me where it is.

Answer;

Yes. For connections the configuration is in conf/transaction-service.xml

<attribute name="Debug">true</attribute>

For statements (and from 3.2.4 ResultSets) you can add the following to
your -ds.xml

<track-statements>true</track-statements>

In production you will want to turn these off. You should have found all your
leaks during development.
Also from 3.2.4 you will want to comment out the cached connection manager valve
that checks for unclosed connections in jsps/servlets.
This is in deploy/jbossweb-xxx.sar/server.xml

 <!-- Check for unclosed connections -->
 <Valve className="org.jboss.web.tomcat.tc5.jca.CachedConnectionValve"
 cachedConnectionManagerObjectName="jboss.jca:service=CachedConnectionManager" />

[adrian.brock]

Question:

Is it possible to shutdown the database and restart it?
Will JBoss complain about stale connections?

Answer;

You can configure the following in your -ds.xml

<check-valid-connection-sql>some cheap sql statement</check-valid-connection-sql>
e.g. for Oracle "select 1 from dual"

JBoss will run the SQL statement before handing out the connection from the pool.
If the SQL fails, the connection will be destroyed/closed and new ones will be created.

Regards,
Adrian

[adrian.brock]

Question:

How can I access a DataSource from a client

Answer:

In JBoss-3.2.x you cannot, DataSources are not exposed remotely.
There is an implementation of this in JBoss4.
I would not recommend this anti-pattern

[guix]

Question:

I am use Oracle XA and getting
"Could not enlist in transaction on entering meta-aware object!"
or
xa error: -3 (A resource manager error has occured in the transaction branch. ; oracle error: 65535; oracle sql error: -1;

Answer:

Check 2 things:
1.- That your jbosscmp-jdbc.xml is specifying the same version of oracle as the one you use.
2.- That the oracle server you connect to has XA enabled as explained in:
http://www.baldor.it/StartPage/documents/admin/59.html
Down the page on "Configuring Oracle Database for XA Support"


Cheers

[hakucho]

"guix" wrote:
... explained in:
http://www.baldor.it/StartPage/documents/admin/59.html
Down the page on "Configuring Oracle Database for XA Support" ...

This link is broken; however I suspect the same info is now here:

http://wiki.jboss.org/wiki/Wiki.jsp?page=IHaveProblemsWithOracleXA

HTH,

Andrew