3:41 p.m.
[
https://issues.jboss.org/browse/ISPN-1546?page=com.atlassian.jira.plugin....
]
Vladimir Blagojevic commented on ISPN-1546:
-------------------------------------------
Ok I think I have gotten to the bottom of why this is happening and why the fail-safe
iterator I prepared is not going to be enough. Take a look at any write operation of
FGAM:
{code}
public V put(K key, V value) {
AtomicHashMap<K, V> deltaMapForWrite = null;
try {
startAtomic();
deltaMapForWrite = getDeltaMapForWrite();
return deltaMapForWrite.put(key, value);
} finally {
invokeApplyDelta(deltaMapForWrite.getDelta());
endAtomic();
}
}
{code}
Recall the actual lock on the non thread safe AtomicHashMap is never obtained - by design.
The locks are obtained per key of AtomicHashMap. Therefore in order to make a snapshot
iterator of AtomicHashMap we have to somehow lock the entire AtomicHashMap for the
duration of iterator creation. This lock also has to be obtained by other write ops on
AtomicHashMap which in turn defeats the purpose of FineGrainedAtomicMap to begin with.
It seems like we are left with an option to use FGAM but without any iteration. If
iteration is needed AtomicMap should be used instead.
Thoughts?
FineGrainedAtomicMap key and value iterators are not threadsafe
---------------------------------------------------------------
Key: ISPN-1546
URL: https://issues.jboss.org/browse/ISPN-1546
Project: Infinispan
Issue Type: Bug
Components: Core API, Locking and Concurrency
Reporter: Sanne Grinovero
Assignee: Vladimir Blagojevic
Invoking #keySet() or #values() might fail, even when using a transaction to isolate
threads:
{code}
java.util.ConcurrentModificationException
at
org.infinispan.util.FastCopyHashMap$FasyCopyHashMapIterator.nextEntry(FastCopyHashMap.java:484)
at org.infinispan.util.FastCopyHashMap$KeyIterator.next(FastCopyHashMap.java:560)
at java.util.AbstractCollection.addAll(AbstractCollection.java:305)
at
org.infinispan.atomic.FineGrainedAtomicHashMapProxy.keySet(FineGrainedAtomicHashMapProxy.java:104)
at
org.hibernate.ogm.dialect.infinispan.InfinispanAssociationSnapshot.getRowKeys(InfinispanAssociationSnapshot.java:59)
at org.hibernate.ogm.datastore.spi.Association.getKeys(Association.java:132)
at org.hibernate.ogm.loader.OgmLoader.getResultSet(OgmLoader.java:420)
at org.hibernate.ogm.loader.OgmLoader.doQuery(OgmLoader.java:248)
at
org.hibernate.ogm.loader.OgmLoader.doQueryAndInitializeNonLazyCollections(OgmLoader.java:215)
at org.hibernate.ogm.loader.OgmLoader.loadCollection(OgmLoader.java:185)
at
org.hibernate.ogm.loader.OgmBasicCollectionLoader.initialize(OgmBasicCollectionLoader.java:42)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:622)
at
org.hibernate.event.internal.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:82)
at org.hibernate.internal.SessionImpl.initializeCollection(SessionImpl.java:1607)
at
org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:379)
at
org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:112)
at org.hibernate.collection.internal.PersistentSet.iterator(PersistentSet.java:180)
{code}
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