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From "Paolo Castagna (JIRA)" <>
Subject [jira] [Commented] (JENA-91) extremely large buffer is being created in ObjectFileStorage
Date Fri, 19 Aug 2011 10:46:27 GMT


Paolo Castagna commented on JENA-91:

Simon, I tried to run with your changes. The warnings in this case are
misleading, a false alarm, since your code adds triples to named graphs while the test checks
for the effects on the default graph. I do not see any error or exceptions.
I also tried to write separate sequential tests using the Jena APIs (as you do) mixed with
with direct calls to DatasetGraph's methods. Once again, I see no errors or exceptions.
The error "ERROR com.hp.hpl.jena.tdb.base.block.BlockMgrCache - write: Block in the read cache",
which you reported above, originates in BlockMgrCache which is used only if
is used. 
There is a flag in TestTransSystem to run in "direct" or "mapped" mode. Once again, I've been
running TestTransSystem in "direct" or "mapped" mode and I see no errors or exceptions.
If you manage to see an error running or any modified version of it,
please, attach a copy of the file to this issue.

> extremely large buffer is being created in ObjectFileStorage
> ------------------------------------------------------------
>                 Key: JENA-91
>                 URL:
>             Project: Jena
>          Issue Type: Bug
>          Components: TDB
>         Environment: Windows (and I presume any little endian system)
>            Reporter: Simon Helsen
>            Assignee: Andy Seaborne
>            Priority: Critical
>         Attachments: TestTransSystem.patch
> I tried to debug the OME and check why a bytebuffer is causing my native memory to explode
in almost no time. It all seems to happen in this bit of code in com.hp.hpl.jena.tdb.base.objectfile.ObjectFileStorage
(lines 243 onwards)
>   // No - it's in the underlying file storage.
>         lengthBuffer.clear() ;
>         int x =, loc) ;
>         if ( x != 4 )
>             throw new FileException(""+loc+")["+filesize+"]["+file.size()+"]:
Failed to read the length : got "+x+" bytes") ;
>         int len = lengthBuffer.getInt(0) ;
>         ByteBuffer bb = ByteBuffer.allocate(len) ;
> My debugger shows that x==4. It also shows the lengthBuffer has the following content:
[111, 110, 61, 95]. This amounts to the value of len=1869495647, which is rather a lot :-)
Obviously, the next statement (ByteBuffer.allocate) causes the OME.

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