10:01 a.m.
Ian Springer [http://community.jboss.org/people/ips] created the discussion
"way too many SLSB instances eventually cause heap to run out"
To view the discussion, visit: http://community.jboss.org/message/586260#586260
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In the RHQ 3.0 server, we use JBossAS 4.2.3's bundled EJB3. A user has reported seeing
way too many SLSB instances slowly building up in heap and eventually causing the server
to run out of heap (see his post from the rhq-devel list below). Can anyone shed some
light on what could be causing it? Is it a bug in the EJB container, a bug in our
application code, or just some configuration setting we need to adjust?
Thanks,
Ian
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Following up a post from about a month ago. We were seeing a
persistent slow memory leak in the rhq server in tenured gen space that eventually led
to an out of memory exception after running the server for about a week. I captured a
heap dump and found hundreds of thousands of stateless session beans in memory.
Here's a snapshot from my profiler of a table of classes with greatest number of
instances.
| Name | Objects | Shallow Size |
Retained Size |
| java.util.HashMap$Entry | 1939755 | 93108240 |
189082696 |
| java.util.HashMap$Entry[] | 1090957 | 167796768
| 340273520 |
| java.util.HashMap | 1084265 | 69392960 |
408521632 |
| java.util.LinkedList$Entry | 860965 | 34438600
| 727956072 |
| org.jboss.ejb3.BaseSessionContext | 856281 | 34251240
| 34251240 |
| org.rhq.enterprise.server.authz.RequiredPermissionsInterceptor |
856281 | 13700496 | 13700496 |
| org.rhq.enterprise.server.common.TransactionInterruptInterceptor |
856281 | 13700496 | 13700496 |
| org.jboss.ejb3.stateless.StatelessBeanContext | 856265 |
68501200 | 490959040 |
| java.lang.String | 429025 | 17161000 | 48902064
|
| char[] | 379454 | 37897872 | 37897872
|
| java.lang.Integer | 171633 | 4119192 | 4119192
|
| java.util.Hashtable$Entry | 157623 | 7565904 |
34980432 |
| java.util.TreeMap$Entry | 105496 | 6751744 |
14950816 |
| java.lang.String[] | 98401 | 4340480 | 6555536
|
| org.rhq.enterprise.server.auth.SubjectManagerBean | 91116
| 6560352 | 49567104 |
| org.rhq.enterprise.server.auth.TemporarySessionPasswordGenerator |
91116 | 3644640 | 43006752 |
| org.rhq.enterprise.server.authz.AuthorizationManagerBean | 91115
| 2186760 | 2186760 |
| org.rhq.enterprise.server.alert.AlertConditionManagerBean | 91084
| 2914688 | 2914688 |
| org.rhq.enterprise.server.alert.AlertManagerBean | 90914
| 9455056 | 9455056 |
| org.rhq.enterprise.server.alert.AlertDefinitionManagerBean | 90911
| 4363728 | 4363728 |
| org.rhq.enterprise.server.alert.AlertConditionLogManagerBean |
90903 | 5090568 | 5090568 |
| org.rhq.enterprise.server.alert.CachedConditionManagerBean | 90903
| 4363344 | 4363344 |
| org.rhq.enterprise.server.alert.AlertDampeningManagerBean | 90903
| 3636120 | 3636120 |
| org.jboss.security.SecurityAssociation$SubjectContext | 49229
| 2362992 | 2362992 |
| org.rhq.enterprise.server.cloud.instance.ServerManagerBean | 39354
| 3463152 | 3463152 |
| org.rhq.enterprise.server.cloud.CloudManagerBean | 39354
| 2833488 | 2833488 |
Here are the merged paths from the SubjectManagerBean to GCRoot:
| <All the objects> |
| org.jboss.ejb3.stateless.StatelessBeanContext |
| java.util.LinkedList$Entry |
| java.util.LinkedList$Entry |
| java.util.LinkedList |
| org.jboss.ejb3.InfinitePool |
| org.jboss.ejb3.ThreadlocalPool |
| org.jboss.ejb3.stateless.StatelessContainer |
All the other manager beans have similar merged paths. So I started to wonder why
there were so many slsb's in the ThreadlocalPools and after some digging found
this ( http://community.jboss.org/message/363520#363520
http://community.jboss.org/message/363520) thread that sort of describes what I'm
seeing. I still don't know why it's happening but it gave me something to
try. I changed the Stateless Bean pool class in ejb3-interceptors-aop.xml from
ThreadlocalPool to StrictMaxPool. Now when I run the server and watch it with my
profiler I see at max 3 SubjectManagerBeans in memory. Same appears to be true for
other slsb's. This isn't a solution to the problem but I'm hoping someone
can shed light on what's really going on. I would be happy to upload the heap dump
to somewhere public but it's almost a GB in size.
Bala Nair
SeaChange International
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