On 02/03/13 10:02, Claude Warren wrote:
First some background.
I am debugging an app and did kill the app in the middle of an execution.
<code>
dataset = TDBFactory.createDataset( "./jena" );
model = dataset.getDefaultModel();
</code>
the getDefaultModel() method throws a null pointer.
in DatasetPrefixesTDB.readPrefixMap()
<code>
public synchronized Map<String, String> readPrefixMap(String graphName)
{
Node g = Node.createURI(graphName) ;
Iterator<Tuple<Node>> iter = nodeTupleTable.find(g, null, null) ;
Map<String, String> map = new HashMap<String, String>() ;
for ( ; iter.hasNext() ; )
{
Tuple<Node> t = iter.next();
String prefix = t.get(1).getLiteralLexicalForm() ;
String uri = t.get(2).getURI() ;
map.put(prefix, uri) ;
}
Iter.close(iter) ;
return map ;
}
</code>
graphName = "";
t = [<null>, <null>, <null> ]
String prefix = t.get(1).getLiteralLexicalForm() ;
throws a null pointer exception.
My question is: What can I do to restore the data? I tried reloading using
tdbloader2 to reload the data but that did not work.
Did you delete the old database? tdbloader2 is (currently) not
prefix-aware so it may be that the old prefix table is being left in
place. Try in a fresh directory.
You can also just go in and delete the prefix table files, prefix*.
An empty prefix table will be recreated on the next start up.
My other question is where should I look to find the problem?
At guess, there was some non-transactional use of the database. A
change to the prefix table did not get completely written (the node file
changes were not written but the tuples part was).
This could be due to an interrupted load or use of TDB non-transactionally.
Andy
