#2249 memory leak after 7 hours

[Mormota]

Hi,

I have experienced strange memory leaks under JBoss
4.0.0 after 7 hours, and under JBoss 4.0.1RC2 after 3.5
hours running my application. (In the first 7 hours my
application consumes 100M of memory under 4.0.0,
however after 7 hours the memory consumption raises
lineraly). I used YourKit to detect the memory leak and
I found that the memory is chiefly occupied by HashMap
and entity bean proxies.

Unfortunately I cannot provide source code, but I can
give a short description of the component architecture
and functioning:
(a) objects are inserted into a messaging topic
(b) an MDB receives the objects and:
(b.i) dispaches them to a resource adapter (the RA
sends the object over the network)
(b.ii) creates a database entry using the String(s)
returned by the RA (a tuple looks like this: [String:
id, Date: date, String: st]; I'm using a CMP entity bean)

(c) a timer periodically removes the overaged database
entries (see date). ejbTimeout is implemented by a
stateless session bean, database entries are removed by
the corresponding CMP entity bean

(d) whenever the RA receives an object over the
network, it dispatches it to a stateless session bean,
which is registered as an endpoint at the RA
(e) the stateless session bean
(e.i) updates the database entry (using the ), or
more precisely, its "st" field
(e.ii) inserts a new database entry
(e.iii) if the "st" field statisfies certain
conditions, removes both the inserted and updated entries

Additional infos:
* OS: RedHat AS (running on various hardware, e.g.
simple PC and a 4 processor Xeon server)
* JDK: jdk1.4.5
* I see lot of log messages regarding rolled back
transactions (because of timeouts); these exceptions
are thrown in the CMP entity bean in that method, which
removes the overaged entries. After a findByDate I
iterate over the resulting collection and when I want
to access "id", an exception is thrown. Not always, but
strangely often.
* the memory leak emerges after 7 (or 3.5) hours
regardless the load, and configuration. The load
influences only the gradient of the lineraly increasing
(and therefore deadly) period.

Merry Christmas,

Mormota

[Mormota]

log file fragments

[Mormota]

Logged In: YES
user_id=1184354

Some new details:
I simplified the application to the following (see new step
b.iii):
(a) objects are inserted into a messaging topic
(b) an MDB receives the objects and:
(b.i) dispaches them to a resource adapter (the RA
sends the object over the network)
(b.ii) creates a database entry using the String(s)
returned by the RA (a tuple looks like this: [String:
id, Date: date, String: st]; I'm using a CMP entity bean)
(b.iii) _removes the new entry_

Despite the database entries are removed instantly after
their creation (and therefore the database is empty), the
memory usade increases steadyly.

In stable JBoss 4.0.1, there is no 3.5 (or 7) hours long
constant-memory-use period.

The pace of memory consumption growth can be reduced by
using C "commit option" (instead of the default B).

Memory leak still persist when using jdk 1.5.

[Scott M Stark]

Logged In: YES
user_id=175228

Please continue on the jira site:
http://jira.jboss.com/jira/browse/JBAS-1255

[Mormota]

Logged In: YES
user_id=1184354

Here is the first example application:
- uses a topic and an MDB to create entities
- uses a timer to remove old entities

[Mormota]

source code

[Mormota]

conf and deploy directories

[Mormota]

lib directory (please also add pg74.215.jdbc3.jar)