Hibernate failing with OutOfMemory when try and close read only session that has read many objects

Question

This code can fail with OutOfMemory Exception when recNos array is large ( >20,000) when I commit the close session. I'm only reading information and only reading one object at a time (the idea was to reduce memory load by reading one at a time) and I only use the object for that invocation in the loop, but I'm not explicitly discarding it. Am I doing something wrong can I explicitly release the memory.

        try
        {
            session = com.jthink.songlayer.hibernate.HibernateUtil.getSession();
            for (Integer next : recNos)
            {
                Song song = SongCache.loadSongFromDatabase(session, next);
                folderToSongIds.put(new File(song.getFilename()).getParent(),song.getRecNo());
            }
        }
        finally
        {
            HibernateUtil.closeSession(session);
        }

This is the stacktrace

java.lang.OutOfMemoryError: GC overhead limit exceeded
at org.hibernate.internal.util.collections.IdentityMap.entryArray(IdentityMap.java:165)
at org.hibernate.internal.util.collections.IdentityMap.concurrentEntries(IdentityMap.java:76)
at org.hibernate.engine.internal.StatefulPersistenceContext.clear(StatefulPersistenceContext.java:237)
at org.hibernate.internal.SessionImpl.cleanup(SessionImpl.java:651)
at org.hibernate.internal.SessionImpl.close(SessionImpl.java:363)
at com.jthink.songlayer.hibernate.HibernateUtil.closeSession(HibernateUtil.java:94)

Can this be due to new instance of File being created everytime ? Too many files getting loaded ? — gvmani
– gvmani, Commented Aug 2, 2014 at 13:37

Khary Mendez · Accepted Answer · 2014-08-02 13:35:15Z

1

You can detach the entity from the session when you are done with it by calling evict:

    {
        Song song = SongCache.loadSongFromDatabase(session, next);
        folderToSongIds.put(new File(song.getFilename()).getParent(),song.getRecNo());
        session.evict(song);
    }

answered Aug 2, 2014 at 13:35

Khary Mendez

1,8581 gold badge15 silver badges19 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Beatles1692 · Accepted Answer · 2014-08-02 14:52:45Z

0

According to this article this exception happens when GC is unable to empty more than 2% of the heap which I think it can mean memory leak.

It seems that you are writing a lot of files which can be a good source of memory leakage.I am not sure if these files are closed after they have been created.

BTW I suggest you use a memory profiler to see what is occupying the heap.

**20% percent was a typo that I updated

edited Aug 2, 2014 at 14:52

answered Aug 2, 2014 at 13:47

Beatles1692

5,35040 silver badges70 bronze badges

2 Comments

Paul Taylor Over a year ago

Don't you mean 2%, its a File object rather than a FileWriter so nothing to close, but perhaps I could use Paths instead of having to construct files in the first place.

Beatles1692 Over a year ago

Anyway my answer was to use a memory profiler.As I mentioned I didn't know how you were creating yuor files

Collectives™ on Stack Overflow

Hibernate failing with OutOfMemory when try and close read only session that has read many objects

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related