It was my problem, not OJB's. My mapping file and Java classes had gotten out of sync (OJB mapping tools are looking very promising now, perhaps it's time to stop manual synchronization...). Garbage collection is now keeping memory use stable. In the past, I had worked around this problem for production use by restarting jBoss every day. Hopefully this will no longer be required. Another benefit: I may be able to finally use a per-broker cache in production. Until now I have had to turn off caching altogether.
Lessons learned:
-manual maintenance of mapping is error-prone. I imagine, though, that even with the new tools, nothing replaces a careful human scan of the java_source/mapping/db_schema ensemble
-the profiler OptimizeIt is very useful for memory leak investigation once learned. Very important to create a minimal test program otherwise the data explosion makes it difficult to isolate problem references.
Phil
Hi all,
I'm in the midst of tracking down a leak that occurs when I do a write operation on an object graph. Garbage collection isn't removing these objects because they are referred to by internal ojb classes. Presumably some internal cleanup isn't occurring properly after each
begin tx ... commit tx cycle.
No leak seems to occur, however, if I simply do a read operation on the same graph.
A preliminary observation that I have made is that for some reason, when I call lock() on the graph root, eventually that graph root is again retrieved from the db, as shown in the trace below (my two notes indicated by <------- xxxx ***). Thus an unnecessary copy is made of the root object, and this copy may not be gc'd because of the ojb references to it that presumably are not cleaned up.
Does anyone have some insights that might help as I look at this under the microscope? (I using the profiler Optimizeit: couldn't find a decent open-source alternative). Is there some extra cleanup that I should be doing using the ODMG api? Is this known behaviour by any chance, or better, already fixed? I'm running 1.0.rc4 with per-broker caching and implicit locking at the moment.
Thanks,
Phil
Allocated at
ConstructorHelper.instantiate() (ConstructorHelper.java:158) <--root object gets instantatiated again here!!! ***
RowReaderDefaultImpl.buildWithReflection() (RowReaderDefaultImpl.java:233)
RowReaderDefaultImpl.readObjectFrom() (RowReaderDefaultImpl.java:116)
RsIterator.getObjectFromResultSet() (RsIterator.java:433)
RsIterator.next() (RsIterator.java:254)
PersistenceBrokerImpl.getCollectionByQuery() (PersistenceBrokerImpl.java:1374)
PersistenceBrokerImpl.getCollectionByQuery() (PersistenceBrokerImpl.java:1515)
PersistenceBrokerImpl.getCollectionByQuery() (PersistenceBrokerImpl.java:1483)
DelegatingPersistenceBroker.getCollectionByQuery() (DelegatingPersistenceBroker.java:307)
DelegatingPersistenceBroker.getCollectionByQuery() (DelegatingPersistenceBroker.java:307)
CollectionProxy.loadData() (CollectionProxy.java:141)
ListProxy.loadData() (ListProxy.java:187)
CollectionProxy.getData() (CollectionProxy.java:375)
CollectionProxy.iterator() (CollectionProxy.java:199)
CollectionProxy.ojbIterator() (CollectionProxy.java:429)
TransactionImpl.lockCollections() (TransactionImpl.java:914)
TransactionImpl.register() (TransactionImpl.java:809)
TransactionImpl.lock() (TransactionImpl.java:291)
TransactionImpl.lockCollections() (TransactionImpl.java:982)
TransactionImpl.register() (TransactionImpl.java:809)
TransactionImpl.lock() (TransactionImpl.java:291)
TransactionImpl.lockReferences() (TransactionImpl.java:1018)
TransactionImpl.register() (TransactionImpl.java:801)
TransactionImpl.lock() (TransactionImpl.java:291)
DB.lock() (DB.java:205) <---------------lock the root object here ***
EventServer.commitEvent() (EventServer.java:621)
EventServerLocal.commitEvent() (EventServerLocal.java:700)
EventServerLoadTest.testEventReadLoad() (EventServerLoadTest.java:135)
NativeMethodAccessorImpl.invoke() ()
DelegatingMethodAccessorImpl.invoke() ()
TestCase.runTest() (TestCase.java:154)
TestCase.runBare() (TestCase.java:127)
TestResult$1.protect() (TestResult.java:106)
TestResult.runProtected() (TestResult.java:124)
TestResult.run() (TestResult.java:109)
TestCase.run() (TestCase.java:118)
TestSuite.runTest() (TestSuite.java:208)
TestSuite.run() (TestSuite.java:203)
TestRunner.doRun() (TestRunner.java:116)
TestRunner.start() (TestRunner.java:172)
TestRunner.main() (TestRunner.java:138)
EventServerLoadTest.main() (EventServerLoadTest.java:49)
NativeMethodAccessorImpl.invoke() ()
DelegatingMethodAccessorImpl.invoke() ()
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