At your service :)
JCA posts:
http://www.jboss.com/index.html?module=bb&op=viewtopic&t=91882
http://www.jboss.com/index.html?module=bb&op=viewtopic&t=91064
http://www.jboss.com/index.html?module=bb&op=viewtopic&t=87175
http://www.jboss.com/index.html?module=bb&op=viewtopic&t=87807
http://www.jboss.com/index.html?module=bb&op=viewtopic&t=61812
hmmmmm....
We solved a lot of our problems by closing the connections. You can turn logging on for
this with the Debug set to true. And no warnings we receive for that anymore. In our code
we open and close connections like this:
| Session s = null;
| try {
| s = SessionLocator.newSession();
| //bla bla
| } catch (Exception e) {
| l.fatal("bla more bla", e);
| } finally {
| try {
| s.close();
| } catch (Exception e) {}
| }
|
We also tried to check closing Resultsets
(<track-statements>true</track-statements>), but that produces a lot of
warnings, the reason for that is we use Hibernate (cannot find forum entry, but it is a
known (non) issue).
We have these problems more or less since JBoss 3, now using 4.0.4. Hibernate vs 2 and
3.1.
mysql-ds:
| <local-tx-datasource>
| <jndi-name>Database</jndi-name>
|
|
<connection-url>jdbc:mysql://localhost:3306/jst_objects?characterEncoding=ISO8859-1&cachePrepStmts=true&jdbcCompliantTruncation=false</connection-url>
| <driver-class>com.mysql.jdbc.Driver</driver-class>
| <user-name>web</user-name>
| <password>1234</password>
| <min-pool-size>5</min-pool-size>
| <max-pool-size>1050</max-pool-size>
| <idle-timeout-minutes>5</idle-timeout-minutes>
<exception-sorter-class-name>com.mysql.jdbc.integration.jboss.ExtendedMysqlExceptionSorter</exception-sorter-class-name>
<valid-connection-checker-class-name>com.mysql.jdbc.integration.jboss.TimeoutMySQLValidConnectionChecker</valid-connection-checker-class-name>
|
<exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>
| <metadata>
| <type-mapping>mySQL</type-mapping>
| </metadata>
| <attribute name="Debug">true</attribute>
| <track-statements>true</track-statements>
| </local-tx-datasource>
|
The database reports:
| show processlist;
|
| | 5864 | web | localhost:57348 | jst_objects | Sleep | 16207 | |
5865 | web | localhost:57104 | jst_objects | Sleep | 16279 |
| | 5866 | web | localhost:42541 | jst_objects | Sleep | 15912 |
| | 5875 | web | localhost:49491 | jst_objects | Sleep | 15806 |
| | 5877 | web | localhost:37892 | jst_objects | Sleep | 15755 |
| ......
| 157 rows in set (0.00 sec)
|
| status;
| .....
| Threads: 155 Questions: 33777278 Slow queries: 0 Opens: 41 Flush tables: 1 Open
tables: 64 Queries per second avg: 244.696
|
|
You can see that MySQL has a lot of unused, idle connections (16207 for example means a
hell of a lot more then <idle-timeout-minutes>5</idle-timeout-minutes>).
With a system load of 250 queries per second, 50 concurrent connections should be enouh.
So, IMHO, there is a lot of drivel on the forums about runaway connections in JCA. And we
have problems with one heavy loaded JBossMQ queue that is stalling. The other queues are
running flawless. My hunch is that the stalling MQ is causing the connections to become
idle. So, i want to remove that and put in another messaging system.
Looking for replacements ActiveMQ for example seems to be a mature replacement for
JBossMQ, but i believe (searching the posts) it cannot be embedded in JBoss when using
MDB:
http://www.jboss.org/index.html?module=bb&op=viewtopic&t=85381
Would be JBoss Messaging be a good replacement candidate? Therefor my post.
Another solution i drivelled would indeed be to drop JCA. It is, looking at the posts and
my experience, proven itchy. Itchy is no problem when the software running on it is
closing connections like they should, but that is with more complex system not always the
case and will always be a threat to the robustness of the system.
anonymous wrote :
| or at the very least post your issue to the JCA forum
|
Especially the JCA forum is a place where i would hesitate to post an issue. Posters often
get cyberkilled there, exemplified by their supposed stupidity:
http://www.jboss.org/index.html?module=bb&op=viewtopic&t=68044
and yet another 'too many connections' would not contribute to the many similar
unanswered posts.
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