APPARENT DEADLOCK!!

jfjimenezp · **Joined:** Tue Apr 19, 2005 6:53 pm **Posts:** 1

I'm developing an application using Oracle 8.1.7, Sun One Studio 5 and Hibernate 2.1.8

While runnig the app I get the following error

com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@5acf13 -- APPARENT DEADLOCK!!

What is the cause?

Thanks.

keule · **Posted:** Fri Apr 22, 2005 6:25 am

http://www.hibernate.org/ForumMailingli ... AskForHelp

wanton · **Joined:** Mon Oct 11, 2004 2:22 am **Posts:** 41

i am also getting this problem while load testing

com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@10ecc43 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!

what are the potential causes?
what can be done to minimise deadlocks?

wanton · **Joined:** Mon Oct 11, 2004 2:22 am **Posts:** 41

ok, i've solved it in our case.

our hibernate config used to have the following:

Code:

props.setProperty("hibernate.c3p0.max_statements", "600");

changed that value to '0' and no longer get deadlocks.

swaldman · **Joined:** Tue Jan 06, 2004 8:58 pm **Posts:** 145

Hi. These deadlocks are most commonly seen under Oracle, using older versions of c3p0. Please upgrade the c3p0-0.9.0-pre6, and try turning statement caching back on. (I'm hoping that the Oracle deadlock sometimes seen with Statement caching turned on has been fixed.) If you do see the deadlock reoccur, please post the deadlock output (which in recent versions of c3p0 is quite extensive) which will indicate exactly what is hanging, and help us figure out exactly what is going on.

(Please, generally with c3p0 issues, post c3p0's version and build banner, and configuration dump.)

Thanks!

Steve (c3p0 guy)

wanton · **Joined:** Mon Oct 11, 2004 2:22 am **Posts:** 41

steve, the old deadlocks were with oracle however while load testing a different application (using hsqldb) i noticed more deadlock issues.

first thing i tried was turning the statement cache off which worked a treat, speeding up the system and eradicating the deadlock errors.

sorry, i don't have time to go thru the logs but we are using the new version of c3p0

natedigby21 · **Joined:** Wed Aug 04, 2010 11:15 pm **Posts:** 1

wanton wrote:

ok, i've solved it in our case.

our hibernate config used to have the following:

Code:

props.setProperty("hibernate.c3p0.max_statements", "600");

changed that value to '0' and no longer get deadlocks.

Thanks for this instruction. It's now working perfectly fine. BTW i am using the new version c3p0.

Regards,