[JBoss-dev] [JBoss JIRA] Commented: (JBAS-1664) Unloaded entities returned in low memory conditions
[ http://jira.jboss.com/jira/browse/JBAS-1664?page=comments#action_12316784 ] Arto Huusko commented on JBAS-1664: --- Yes, sorry, I do mean OutOfMemoryError. However, if it is true that JVM is unusable after OutOfMemoryError, JBoss should be changed to terminate immediately the first time it sees that error. And, I'm curious as to why the JVM itself bothers to throw an error, if it really is so that application can never do anything to recover. The fact is that in the face of OutOfMemoryError, the JVM really was surprisingly usable and in working state. Our code was able to do some real work off and on for hours while also seeing OOMEs -- but also some damage, when those BMP beans started misbehaving. And we had a heavily tweaked configuration: BMP beans with commit option A, maximum cache size of 1 instances and maximum memory of 1GB (which, though, is a slightly moot point because at the time we were bitten by issue JBAS-1662). Anyway, I feel very strongly that something should be done about this, even if it is that immediate termination of JVM, because otherwise some really bad things can happen if there is some other problem (be it in JBoss or application) that causes the JVM to run out of memory. Unloaded entities returned in low memory conditions --- Key: JBAS-1664 URL: http://jira.jboss.com/jira/browse/JBAS-1664 Project: JBoss Application Server Type: Bug Components: EJBs Versions: JBossAS-3.2.6 Final Reporter: Arto Huusko In low memory conditions (that is, when OutOfMemoryExceptions are seen frequently all over the place), JBoss can behave wrong in a way that is critically wrong. I have seen on several occasions that a finder returns an entity with the correct identity, but where ejbLoad() has either not been called at all, or where ejbLoad() has failed at some point (I have no way of knowing which is the case). I have observed this behaviour only with BMP beans (and so there is a possibility that I am doing something wrong in the BMP code, but I doubt this). However, the fact that I haven't seen this with CMP beans may be just because CMP beans work differently, or just plain luck. When this occurs, the wrong behaviour can be seen because the instance variables of the entity bean contain what ever they had when the entity instance was previously attached to some other identity. For example, I may store the primary key of the entity in some instance variable. Let's say I can access the primary key via method Long getMyPrimaryKey(). If the finder returns an entity with the correct identity (what I asked for in the finder call), but where ejbLoad() is not called or it fails, then entity.getMyPrimaryKey().equals(entity.getPrimaryKey()) is false. And this is exactly what I have seen. I have no idea where the problem is, and, as I said above, it may be a problem with my code. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://jira.jboss.com/jira/secure/Administrators.jspa - If you want more information on JIRA, or have a bug to report see: http://www.atlassian.com/software/jira --- SF email is sponsored by - The IT Product Guide Read honest candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595alloc_id=14396op=click ___ JBoss-Development mailing list JBoss-Development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jboss-development
[JBoss-dev] [JBoss JIRA] Created: (JBAS-1662) Memory leak with SpecCompliant=true in transaction-service.xml
Memory leak with SpecCompliant=true in transaction-service.xml -- Key: JBAS-1662 URL: http://jira.jboss.com/jira/browse/JBAS-1662 Project: JBoss Application Server Type: Bug Components: Transaction Manager service Versions: JBossAS-3.2.6 Final Environment: jboss 3.2.6, linux 2.[46], DB2 7.[12] Reporter: Arto Huusko If SpecCompliant is set to true in transaction-service.xml, jboss begins to leak memory on a massive scale: all entity beans (both CMP and BMP) that become unused (that is: they are flushed from cache, and instance pool is full, so they are discarded) are never garbage collected. I don't pretend to understand the problem fully (I was in quite a rush to solve the memory leaks and it still took me over a week). I investigated the matter with a home-grown memory profiler, and found out that the leak ultimately occurs in org.jboss.resource.connectionmanager.CachedConnectionManager, which never releases the KeyConnectionAssociation objects (that are stored in a ThreadLocal LinkedList). And since KeyConnectionAssociation also holds a reference to the entity object, the entity objects leak once they are thrown out of the pool. And those KeyConnectionAssociation objects are of course created as a result of the entity beans opening connection to the database. I never found out why the KeyConnectionAssociation objects were never removed from the list (which would have resulted in garbage collection of the entity and all). I just saw somewhere in the code promising references to SpecCompliant, and thankfully it solved the problem for me. Note that leakage also occurs (immediately) if JBoss gets an entity from instance pool to run a finder, and the finder throws an exception. In that case, the entity used to run the finder is leaked immediately (the leakage happens in the same way as outlined above). I marked this problem for 3.2.6, but as far as I can see, the problem is the same in 3.2.7 and 4, too. Maybe priority should really be minor, since I'm not sure that many people use SpecCompliant. Oh, and I also have Debug=true in transaction-service, if that makes any difference. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://jira.jboss.com/jira/secure/Administrators.jspa - If you want more information on JIRA, or have a bug to report see: http://www.atlassian.com/software/jira --- SF email is sponsored by - The IT Product Guide Read honest candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595alloc_id=14396op=click ___ JBoss-Development mailing list JBoss-Development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jboss-development
[JBoss-dev] [JBoss JIRA] Created: (JBAS-1663) unsetEntityContext never called
unsetEntityContext never called
---
Key: JBAS-1663
URL: http://jira.jboss.com/jira/browse/JBAS-1663
Project: JBoss Application Server
Type: Bug
Components: EJBs
Versions: JBossAS-3.2.6 Final
Reporter: Arto Huusko
When entity instances are discarded, according to EJB 2.1 unsetEntityContext()
should be called (although, for some reason, this is not mentioned in Container
Provider Responsibilities, section 10.5.2 makes it quite clear that bean
providers may rely on unsetEntityContext() being called). As far as I can see
(and have tested slightly), unsetEntityContext() is never called in JBoss.
The problem can be seen in org.jboss.ejb.plugins.AbstractInstancePool.free():
if the pool is full, nothing spectacular is done; the entity instance is simply
left alone, which causes it to be GC at some time.
I believe, this code should be in the method:
// this already is there
if (pool.size() maxSize)
{
pool.addFirst(ctx);
}
// add something like this
else
{
ctx.discard();
}
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://jira.jboss.com/jira/secure/Administrators.jspa
-
If you want more information on JIRA, or have a bug to report see:
http://www.atlassian.com/software/jira
---
SF email is sponsored by - The IT Product Guide
Read honest candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595alloc_id=14396op=click
___
JBoss-Development mailing list
JBoss-Development@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/jboss-development
[JBoss-dev] [JBoss JIRA] Created: (JBAS-1664) Unloaded entities returned in low memory conditions
Unloaded entities returned in low memory conditions --- Key: JBAS-1664 URL: http://jira.jboss.com/jira/browse/JBAS-1664 Project: JBoss Application Server Type: Bug Components: EJBs Versions: JBossAS-3.2.6 Final Reporter: Arto Huusko In low memory conditions (that is, when OutOfMemoryExceptions are seen frequently all over the place), JBoss can behave wrong in a way that is critically wrong. I have seen on several occasions that a finder returns an entity with the correct identity, but where ejbLoad() has either not been called at all, or where ejbLoad() has failed at some point (I have no way of knowing which is the case). I have observed this behaviour only with BMP beans (and so there is a possibility that I am doing something wrong in the BMP code, but I doubt this). However, the fact that I haven't seen this with CMP beans may be just because CMP beans work differently, or just plain luck. When this occurs, the wrong behaviour can be seen because the instance variables of the entity bean contain what ever they had when the entity instance was previously attached to some other identity. For example, I may store the primary key of the entity in some instance variable. Let's say I can access the primary key via method Long getMyPrimaryKey(). If the finder returns an entity with the correct identity (what I asked for in the finder call), but where ejbLoad() is not called or it fails, then entity.getMyPrimaryKey().equals(entity.getPrimaryKey()) is false. And this is exactly what I have seen. I have no idea where the problem is, and, as I said above, it may be a problem with my code. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://jira.jboss.com/jira/secure/Administrators.jspa - If you want more information on JIRA, or have a bug to report see: http://www.atlassian.com/software/jira --- SF email is sponsored by - The IT Product Guide Read honest candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595alloc_id=14396op=click ___ JBoss-Development mailing list JBoss-Development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jboss-development
