mananthakris wrote:
Thanks for the quick response.We are using OJB1.0rc4.
ops! This is really outdated.
yes we can use
getObjectByIdentity. But the stack trace of the error shows that
getObjectByQuery is internally calling getObjectByIdentity,so did not think
this would help.
yep, agree with you. If PB.getObjectByIdentity is used it's possible
that OJB find the object in the cache without executing a DB query.
How can we find how many objects are materialized at a
given time?
That's not easy. OJB hasn't methods to trace count of materialized
objects. You could try to log sql statements.
I think if OJB would materialize millions of objects you would get
memory errors with less user too (but as you said the problem only
occurs under heavy load).
Here since it is byPrimarykey i am assuming at this point of time it is
trying to materialize only one object or its all related objects too.
Also what does that the stack trace mean by saying that getObjectByIdentity
calls getReferencedObject and persistenceBrokerImpl.retrieveCollections
(does it try to get all related objects if an object is requested?)
On materialization of an object OJB always loops over all
ReferenceDescriptor of an object and checks if the reference have to be
materialized too or if a proxy object have be used or if nothing have to
be done. Thats why you see persistenceBrokerImpl.retrieveCollections...
methods calls in the stack trace.
Attached is the OJB.properties file and our repository file
In the attachment repository_database.xml is missing.
regards,
Armin
Armin Waibel wrote:
Hi,
could you post the OJB.properties and jdbc-connection-descriptor too?
This would help to find problematic settings.
Which version of OJB do you use?
mananthakris wrote:
Hi,
We are using OJB with Jboss,Mysql on linux.
We have implemented all we could as suggested by OJB performance
tutorial.
We are using Proxies,default cache,PB-api,odmg transaction,but we can't
use
getIteratorByQuery because the results are processed after the
transaction
is closed. We are facing outofmemory error in two places always. One
while
materializing subject from proxy and two using getObjectByQuery for
finding
an object by primarykey.
Isn't it possible to lookup the object by Identity instead of using a
query?
http://db.apache.org/ojb/docu/tutorials/pb-tutorial.html#Find+object+by+primary+key
It happens only if a lot of users around 200 are
using the system.
How many objects are materialized?
regards,
Armin
We have two tier systems with jboss running on a linux
machine with 4GB ram and we have also finetuned jvm options that has
reduced
frequency of OutOfMemoryError (we use -Xms768M -Xmx768M -XX:NewSize=256M)
Any suggestions are appreciated? Should we be looking at mysql
performance,any good tools for profiling ojb?
Here is the stack trace of two errors
1)java.lang.OutOfMemoryError
rethrown as
org.apache.ojb.broker.PersistenceBrokerException
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getCollectionByQuery(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveCollection(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveCollections(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getExtentDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByIdentity(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getReferencedObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveReference(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveReferences(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByIdentity(Unknown
Source)
at
org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByIdentity(Unknown
Source)
at
org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByIdentity(Unknown
Source)
at
org.apache.ojb.broker.accesslayer.IndirectionHandler.materializeSubject(Unknown
Source)
at
org.apache.ojb.broker.accesslayer.IndirectionHandler.getRealSubject(Unknown
Source)
at org.apache.ojb.broker.VirtualProxy.getRealSubject(Unknown
Source)
at
com.tk20.bo.BaseServerObjectProxy.realSubject(BaseServerObjectProxy.java:46)
at
com.tk20.bo.BaseServerObjectProxy.getRelatedObjects(BaseServerObjectProxy.java:334)
at
com.tk20.ejb.api.query.QueryMgrEJB.getList(QueryMgrEJB.java:83)
2)java.lang.OutOfMemoryError
rethrown as
org.apache.ojb.broker.PersistenceBrokerException
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getCollectionByQuery(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveCollection(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveCollections(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getExtentDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByIdentity(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getReferencedObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveReference(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveReferences(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getExtentDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByIdentity(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getReferencedObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveReference(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveReferences(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getExtentDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByIdentity(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getReferencedObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveReference(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.retrieveReferences(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByIdentity(Unknown
Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByQuery(Unknown
Source)
at
org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByQuery(Unknown
Source)
at
org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByQuery(Unknown
Source)
at
com.tk20.ejb.api.BaseServiceEJB.findByPrimaryKey(BaseServiceEJB.java:189)
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http://www.nabble.com/file/4504/OJB.properties OJB.properties
http://www.nabble.com/file/4505/repository.xml repository.xml
http://www.nabble.com/file/4506/repository_user.xml repository_user.xml
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repository_internal.xml
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