Perhaps the first line of work could be to contact the authors and ask them:
Did you contact Jena (or for that matter, any of the other projects) for this work? Why did you use such an old version
of Jena?
Would you be willing to try again with a modern version? If the results are significantly different (as they almost
certainly will be) would you be willing to make an emendation for your workshop paper?
ajs6f
Marco Neumann wrote on 10/19/17 12:10 PM:
just on a side note since this is "only" a workshop contribution it
will not make an appearance in the conference itself and will not
appear in the main ISWC 2017 conference proceedings published by
Springer but only as an independent publication of the workshop
itself.
responsibility for the workshop sits with the Organising Committee
Axel-Cyrille Ngonga Ngomo, Institute for Applied Informatics, Leipzig, Germany
Anastasia Krithara, National Center for Scienti c Research
“Demokritos”, Athens, Greece
Irini Fundulaki, ICS-FORTH, Heraklion, Crete, Greece
and for review the Program Committee
Milos Jovanovik, OpenLink Software, United Kingdom
Pavlos Fafalios, University of Hannover. Germany
Kostas Stefanidis, University of Tampere, Finland
Muhammad Saleem, AKSW, University of Leipzig, Germany
Manolis Terrovitis, IMIS, RC Athena, Greece
Ricardo Usbeck, University of Leipzig, Germany
George Papastefanatos, IMIS RC Athena, Greece
Stasinos Kostantopoulos, NCSR Demokritos, Greece
On Thu, Oct 19, 2017 at 3:51 PM, <[email protected]> wrote:
I hadn't intended to spend time at the benchmarking sessions at ISWC, but if
it seems useful, I can try and raise this issue in person. I suppose partly
it's a question of setting the record straight, and then partly it's a
question of standing up for good practice, and then it's also a question of
protecting Jena from unmerited negative consequences.
I don't know how widely used such benchmarks are. Except for a few
high-profile projects, I rarely see anyone refer to this sort of evidence as
a reason to or not to adopt a system.
ajs6f
Marco Neumann wrote on 10/19/17 9:26 AM:
Rob,
unfortunately this is more common in Semantic Web research papers than
one might expect. I have seen this before in particular with regards
to perceived shortcomings of jena or its components. It might be a
good idea to bring this to the attention of affiliated people in the
organisation (here University of Southampton and Koblenz-Landau ).
while I don't think this is an intentional attempt to bring Jena into
disrepute the situation could be clarified and addressed by the ISWC
workshop or track chair as well. I wish your mentioned "standard
Industry and research practice" would be more common than it currently
is.
btw the thesis report is dated Juli 2016
On Thu, Oct 19, 2017 at 12:08 PM, Rob Vesse <[email protected]> wrote:
Marco
I don’t believe anyone has tried to contact them yet
I think that the complaints here are that there doesn’t appear to have
been any attempt to report the issues identified back to the projects
studied. If this was a security flaw in the project the standard Industry
and research practice would be to make a responsible disclosure to the
projects in advance of the public disclosure such that the researchers and
projects can work together to resolve the problem. The implication being
that it is irresponsible for the authors to benefit from pointing out flaws
in the projects while appearing to make no efforts to help report/resolve
those issues.
As you suggest this paper does appear to be based upon some thesis work,
that thesis indicates that the research was originally carried out in 2015
implying that the author knew of the issue two years ago.
The project has a relatively small core of developers most of whom work
on Jena on the side. We very much rely upon the wider community to provide
input on bugs that need to be resolved e.g. Performance issues and the
features we should prioritise. When someone clearly knew of a problem but
didn’t tell us that is inevitably frustrating for the project.
Rob
On 19/10/2017 10:08, "Marco Neumann" <[email protected]> wrote:
did you try to contact Daniel Janke, Adrian Skubella or Steffen Staab
to get a response?
the findings seem to based on work that has been published online as
part of a bachelor’s thesis by Adrian Skubella.
https://west.uni-koblenz.de/sites/default/files/studying/theses-files/bachelorarbeit-adrian-skubella-benchmarks-for-sparql-property-paths.pdf
On Thu, Oct 19, 2017 at 10:54 AM, Lorenz B.
<[email protected]> wrote:
> For me this is really bad practice. It also looks like they did the
> benchmark more than one year ago. Otherwise due to JENA-1195 this
error
> wouldn't occur anymore. And submission deadline was August 6th,
2017 .
> Their experiments contain 8 queries, rerunning those shouldn't take
ages...
>
> I'm currently trying to reproduce the results of the paper, but the
> whole experimental setup remains unclear. I'm wondering if they
used
> just the Jena CLI or TDB. The same holds for RDF4J. I'm puzzled
because
> the runtimes in the eval section are quite small, but even loading
the
> data of their benchmark takes much more time. So maybe they used
the
> RDF4J server.
>
> The worst thing is that they didn't contact any of the developers.
Or
> did they talk to somebody here and then Andy created the ticket
> JENA-1195? Also for the other queries that failed, I would expect
to see
> tickets on Apache JIRA or at least a hint on the Jena mailing
list...
>
> @Andy I'm also wondering whether JENA-1317 addresses the problem
with
> the empty result of benchmark query containing an inverse property
path.
>
>
> On 18.10.2017 17:03, [email protected] wrote:
>> As you know, Andy, I'm going to ISWC this year-- shall I
buttonhole
>> them and give them our POV? :grin:
>>
>> In all seriousness, from what I can tell the results amount to
"Using
>> older versions of our comparands and without contacting the
projects
>> in question we couldn't find a store that implements every
property
>> path feature correctly and some fail entirely."
>>
>> I'm not really sure how useful that information is...? But I am
ready
>> to do a benchmarking paper for next year. Seems like it's a lot
easier
>> than I thought!
>>
>>
>> ajs6f
>>
>>
>> Andy Seaborne wrote on 10/17/17 9:28 AM:
>>> Hi Lorenz,
>>>
>>> Looks like JENA-1195 which is fixed. Does that look like it?
>>>
>>> I think it is shame when papers focus on bugs rather than
discussing
>>> and even fixing them. Bugs aren't research.
>>>
>>> Path evaluation could improved to stream in more cases (that's
why
>>> LIMIT didn't help), but 1195 explains the slowness
>>> and memory.
>>>
>>> Andy
>>>
>>> On 17/10/17 07:58, Lorenz B. wrote:
>>>> Hi,
>>>>
>>>> I just walked through the papers for the upcoming ISWC
conference and
>>>> found a paper about benchmarking of SPARQL property paths [1] .
>>>>
>>>> Not sure if this is relevant, but it looks like Jena has some
issues
>>>> with different types of queries using the property path. For
example,
>>>>
>>>> SELECT ?o WHERE {A B* ?o.} LIMIT 100
>>>>
>>>> lead to an OOM error on non-cyclic data. Here is the relevant
part of
>>>> the paper:
>>>>
>>>>> While benchmarking Virtuoso, RDF4J and Allegrograph no errors
or
>>>>> exceptions have occurred. During the benchmark process of Jena
an
>>>>> OutOfMemoryError has been thrown whenever a query with the *
operator
>>>>> was used. In order to identify the cause of the error, the
amount of
>>>>> results the query should return has been limited to 100. The
results
>>>>> that have been returned by a query of the form SELECT ?o WHERE
{A B*
>>>>> ?o.} LIMIT 100 where A and B are valid IRIs, consisted of 100
times A.
>>>>> Due to this fact it is presumable that the query containing the
*
>>>>> operator returns A recursively until the main memory was full.
To
>>>>> ensure that this behaviour is not caused by cycles in the
dataset a
>>>>> query of the same form but with a predicate IRI that did not
exist in
>>>>> the dataset was executed. This query still returned 100 times
A. This
>>>>> indicates, that the * operator is not implemented correctly.
>>>> In addition, the experiments showed that:
>>>>> Due to the problems with the * operator the queries 4, 7 and 8
could
>>>>> not be processed. Additionally query 3, 5, and 6 returned no
results
>>>>> after 1 hour and thus, were aborted. Query 1 returned an empty
and
>>>>> thus, incomplete result set. Only for query 2 a valid result
was
>>>>> returned. Due to the lack of comparable results, Jena has been
omitted
>>>>> in the comparison of triple stores.
>>>>
>>>> In the discussion section, they summarize the overall
performance of
>>>> Jena by
>>>>
>>>>> Jena could not return results for any query in under 1 hour
besides
>>>>> query 2. Furthermore, the * operator could not be evaluated at
all and
>>>>> the inverse operator returned empty result sets.
>>>>
>>>> It looks like they used version 3.0.1, so maybe this doesn't
hold
>>>> anymore for all of the queries. If not, it could be interesting
to
>>>> improve performance and/or completeness.
>>>>
>>>> I hope I didn't miss some open JIRA ticket, but in general I
just
>>>> wanted
>>>> to highlight the presence of some published benchmark for those
kind of
>>>> queries.
>>>>
>>>>
>>>> Cheers,
>>>>
>>>> Lorenz
>>>>
>>>> [1] http://ceur-ws.org/Vol-1932/paper-04.pdf
>>>>
>
--
---
Marco Neumann
KONA
