On 25/04/11 09:27, Mohamed Morsey wrote:
Hi all,
I'm doing a kind of benchmarking on triple stores using DBpedia dataset,
and I'm using Jena-TDB as one of them.
I've installed Joseki server, and configured its config file to use this
dataset.
Versions?
But when I try to benchmark Jena through Joseki, the performance of
Jena-TDB is very low and too many queries time out.
I've assigned 8GB of memory to Joseki.
So you are on a 64 bit machine.
The heapsize does not matter much - TDB is using memory mapped files.
Set it to 1G of so; more will slow the machine down a bit as Joseki will
use that much heap eventually, forcing out memory mapped files.
How big is the machine?
Who or what is doing the timeout?
I've also tried to query the DBpedia graph directly using
"TDBFactory.createDataset" and "QueryExecutionFactory.create", but when
I iterate through the returned "ResultSet" either with simple loop or
with "ResultSetFormatter.consume", it works only for the first few
queries and afterwards an Exception of type
"com.hp.hpl.jena.tdb.base.block.BlockException" is always thrown.
That suggests the dataset has been previously corrupted. (A current
version of TDB wil have altered you to any concurrent modifications;
older versions can be corrupted by that as well).
By the way, Fuseki might be user to use for you.
Any help will be appreciated.
Andy
