2012/5/3 Andy Seaborne <a...@apache.org>:
> On 30/04/12 06:50, Tayfun Gökmen HALAÇ wrote:
>>
>> Thank you for your answer Andy.
>>
>> I have already autoReconnect=true in my configuration file. Here's my SDB
>> store configuration. Is there any mistake?
>>
>> <#sdbvoidstore>  rdf:type sdb:Store  ;
>>     rdfs:label "SDB" ;
>>     sdb:layout         "layout2" ;
>>     sdb:connection
>>     [ rdf:type sdb:SDBConnection ;
>>        sdb:sdbType        "MySql" ;
>>        sdb:sdbHost        "localhost" ;
>>        sdb:sdbName        "voidstore" ;
>>    sdb:sdbUser"****";
>>    sdb:sdbPassword"****";
>>    sdb:driver "com.mysql.jdbc.Driver" ;
>>    sdb:jdbcURL "jdbc:mysql://localhost/voidstore?autoReconnect=true" ;
>>     ]
>>     .
>>
>> The first point is that Joseki does not catch a QueryStageException which
>> encapsulates mysql connection exception. It catches a JenaException.
>
>
> I'm not sure why QueryStageException is being raised.  In the rest of the
> description are you using sdb:Model?

There is a sdbModel description at the beginning of the configuration file.

[] ja:loadClass "com.hp.hpl.jena.sdb.SDB" .
sdb:DatasetStore  rdfs:subClassOf  ja:RDFDataset .
sdb:Model rdfs:subClassOf  ja:Model .   

Although execQueryProtected() method in SPARQL class expects mysql
exception within a QueryStageException, it is thrown within a
JenaException by SDB.

>>
>>
>> My modified SPARQL processor cannot obtain a connection although it tries
>> for the second time and autoreconnect is enabled.
>
>
> That should work.

Unfortunately does not work.

>
> One way to keep the connection alive is to ask a lightweight query every
> hour, e.g "ASK{:x :p :o}" -- the IRIs do not have to be in the data.

I have constructed a quartz scheduler to send a query once every four
hours while connection timeout of MySQL is eight hours.

Which one of the following queries is low-cost?

"ASK{:x :p :o}" or "SELECT * WHERE {?s ?p ?o.} LIMIT 1"

>
>        Andy
>
>>
>> Tayfun
>>
>>
>> On 27/04/12 17:01, Tayfun Gökmen HALAÇ wrote:
>>>
>>> Andy,
>>>
>>> Do you have any comments on Joseki SPARQL processor? Message are answered
>>> on a "when I can basis" My expeirnece was that if autoreconnect is enabled,
>>> then the first call
>>
>> after a long idle period still failed.  Retrying was necessary. But you
>> still need autoreconnect. Andy
>
>

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