I want to make sure that whatever is done with this stuff, is that it is configurable in such a way that it can be removed for our benchmarking purposes, and performance tuning in general.

Even a lightweight check will add overhead that we cannot afford if we are to be competitive with IBM and Oracle on SPECjEnterprise2010.  Besides, this is a debugging exercise, not something that should ever really be on in a production environment, in my opinion.

Andy

---

From: "Jaikiran Pai" <jpai@redhat.com>
To: jboss-as7-dev@lists.jboss.org
Sent: Tuesday, October 18, 2011 11:42:30 PM
Subject: Re: [jboss-as7-dev] Better handling of transaction leaks?

Just to be clear, I wasn't in favour of introducing that entire
CachedConnectionValve (which definitely is quite heavy). That link was
more of a reference to show how it was handled in previous versions.

Like you say, it should be easy to check the tx status with a simple check.

-Jaikiran

On Wednesday 19 October 2011 12:09 AM, Jason T. Greene wrote:
> On 10/18/11 12:31 PM, Remy Maucherat wrote:
>> On Tue, 2011-10-18 at 21:28 +0530, Jaikiran Pai wrote:
>>> While looking into a test failure I noticed that currently user
>>> applications can end up leaking transactions (associated with the
>>> invocation thread):
>>>
>>> Servlet {
>>>
>>>       doGet() {
>>>         UserTransaction.begin();
>>>         doSomeOp();
>>>         fail();
>>>         // no tx rollback/commit
>>>       }
>>> }
>>>
>>> Subsequent transactions on that thread can lead to failures and other
>>> sorts of issues. Looking back at previous versions of AS, we had a valve
>>> http://anonsvn.jboss.org/repos/jbossas/trunk/tomcat/src/main/java/org/jboss/web/tomcat/service/jca/CachedConnectionValve.java
>>> which used to cleanup (and log an error) about the leaking transactions.
>>>
>>> Do we want something similar for AS7? Also, are there other "entry
>>> points" (like servlets for web requests) where such leaks can happen and
>>> needs to be taken care off?
>>
>> JPA has automatic tracking of this sort of things using a valve (and
>> added only when needed).
>>
>> For the insignificant amount of people that will do manual transactions
>> and can't be bothered to code properly, everyone gets to pay the cost of
>> transaction tracking for all requests to the web container, so I am
>> against this feature.
>>
>> I remember being flamed pretty badly for daring disabling this "nice"
>> valve by default in AS 6 :) Hopefully it will go better this time.
>>
>
> I'll support you (I'd rather have the perf by default). It seems like it
> should be possible to come up with a fast solution though, instead of
> using the slow CCV. For example its pretty cheap to check the UT
> threadlocal and see if the status is still active (hence a leak).
>

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