Hi Andy,
the database was created from the web interface, and I've only used the web
interface to add data to it, so no other version has ever touched it.
If I understand you correctly, the problem is with the database as a whole, so
dropping and reloading the graph might not solve the problem. I have now
switched to a fresh database and am currently reloading the data, so I can see
whether the problem persists beyond the original database.
The only backup I have done is by making snapshots of the entire virtual server
this is running on, so I don't think that is related in any way.
Thanks again for your help,
Andreas
________________________________
Von: Andy Seaborne <a...@apache.org>
Gesendet: Freitag, 8. März 2019 10:50:28
An: users@jena.apache.org
Betreff: Re: AW: AW: Error 500: No conversion to a Node: <RDF_Term >
Hi Andreas,
Is this a database that has only ever been used with 3.10.0 or was the
data loaded with a previous version at some time in the past?
The problem occurs silently during loading. There is no sign of the
problem at the time and the system works just fine while the RDF term,
or terms, are also in the node table cache.
Then the system is restarted.
Then the RDF term is needed for a query and the errors are reported.
But the problem originated back when the data was loaded or updated, may
be several restarts ago.
Of course, it may be a different issue in which case, but the error
message is consistent with the known bug.
Have you been backing up the server on a regular basis? A backup is
NQuads so it is pulling every RDF term from disk (subject to already
being cached).
Andy
On 07/03/2019 20:47, Walker, Andreas wrote:
> Hi Andy,
>
>
> I am running Version 3.10.0. The problem with reloading the database is the
> regular (multiple times a day) recurrence of the problem, so if there are any
> strategies to avoid it, I'd appreciate any advice.
>
>
> Best,
>
> Andreas
>
>
> ________________________________
> Von: Andy Seaborne <a...@apache.org>
> Gesendet: Donnerstag, 7. März 2019 21:12
> An: users@jena.apache.org
> Betreff: Re: AW: Error 500: No conversion to a Node: <RDF_Term >
>
> Hi Andreas - which version are you running?
>
> It does not look like the corruption problem, which is now fixed.
>
> The best thing to do is reload the database again. Whatever terms were
> messed up are permanently damaged I'm afraid.
>
> Andy
>
> On 07/03/2019 10:49, Walker, Andreas wrote:
>> Dear all,
>>
>>
>> as a quick follow-up which might be helpful in identifying the error; I can
>> currently run a SPARQL query (just listing any triples) with LIMIT 80, but
>> no higher, before I run into the error, so it seems like there might indeed
>> be a particular part of the database that is corrupted.
>>
>>
>> Best,
>>
>> Andreas
>>
>> ________________________________
>> Von: Walker, Andreas <andreas.wal...@sub.uni-goettingen.de>
>> Gesendet: Mittwoch, 6. März 2019 10:42:32
>> An: users@jena.apache.org
>> Betreff: Error 500: No conversion to a Node: <RDF_Term >
>>
>> Dear all,
>>
>>
>> from time to time, my Fuseki server starts throwing the following error
>> message on any SPARQL query I pose to one of my graphs:
>>
>>
>> "Error 500: No conversion to a Node: <RDF_Term >"
>>
>>
>> Unfortunately, I couldn't find any explanation of this error message, beyond
>> a discussion of a corrupted TDB2 database.
>>
>>
>> (https://users.jena.apache.narkive.com/LF4XE801/corrupted-tdb2-database)<https://users.jena.apache.narkive.com/LF4XE801/corrupted-tdb2-database>
>>
>>
>> Once this happens, the only thing I could do so far is to drop the entire
>> afflicted graph and rebuild it, but of course that isn't going to be a
>> viable solution in the long term.
>>
>>
>> The only way I interact with Fuseki is by starting and stopping it, querying
>> it via the SPARQL endpoint (and sometimes through the web interface, e.g.
>> when troubleshooting my application), and uploading new triples (as turtle
>> files) via the web interface. I haven't been able to find a pattern in when
>> the error appears so far.
>>
>>
>> Any insights into why this error appears, and what to do in order to avoid
>> it? I'd appreciate any help.
>>
>>
>> Best,
>>
>> Andreas
>>
>
