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It was Sebastian Trüg who said at the right time 20.10.2009 12:43 the
following words:
<blockquote cite="mid:200910201243.23656.trueg@kde.org" type="cite">
<pre wrap="">On Thursday 15 October 2009 21:51:24 Leo Sauermann wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi Sebastian,
from my experience:
</pre>
</blockquote>
<br>
<blockquote type="cite">
<pre wrap="">
* close/disconnect/dispose (however you put it). A repository connection
must be explicitly closed.
</pre>
</blockquote>
<pre wrap=""><!---->
Question is: do we actually need a close method or is it enough to simply
delete the object. The only reason I could think of for a close method is to
match an existing isOpen or isConnected method which is necessary.
</pre>
</blockquote>
All the database apps I used in my programming life had something like
"close", be it ODBC, JDBC, or Sesame. In
non-java-garbage-collected-bliss you usually close/dispose objects that
take memory.<br>
As a connection can have uncommitted changes, it takes memory.<br>
<br>
<br>
<blockquote cite="mid:200910201243.23656.trueg@kde.org" type="cite">
<pre wrap="">
</pre>
<blockquote type="cite">
<pre wrap="">* dirty reads - the repositoryconnection must support dirty reads of its
own changes in the listStatement AND SPARQL implementations - this is a
major issue in nepomuk-java which I implemented in ClientSession and
diffmodelset, and having dirty reads on your connection-aware changes
with SPARQL support is the best way to go, although the hardest to
achieve. It allows to build nice guis showing the results "as if
commited" while not having commited yet. Note, that dirty reads are very
unlikely to work for text indexing.
</pre>
</blockquote>
<pre wrap=""><!---->
I think this is up to the backend. Some backends might not support that.
</pre>
</blockquote>
yep, Sesame is picky to that. But it is nice to have.<br>
and if different backends behave *differently* each time, you can't use
the dirty reads reliably and won't benefit from it. <br>
<br>
well, dirty read with SPARQL is a dream of me to have, I don't think
the backends support it now (didn't look for a year now), so ignore
that... :-|<br>
<br>
<blockquote cite="mid:200910201243.23656.trueg@kde.org" type="cite">
<pre wrap="">
</pre>
<blockquote type="cite">
<pre wrap="">* writing to the repository should not invalidate open readers and
queries. It sucks hard when RDF apis suddenly "fail" in a half-iterated
query result when you concurrently do changes. An iterator should be
valid from start to end, despite doing changes to the same
repositoryconnection while the iterator is open. If this is not
supported, it pushes a lot of hassle to the individual developer
</pre>
</blockquote>
<pre wrap=""><!---->
I think writes should not be possible on a connection with an open
iterator/cursor. If an application needs to read and write at the same time it
opens two connections, right?
</pre>
</blockquote>
sounds clunky to me to have two connections open at the same time. but
alas, so be it. document it!<br>
<blockquote cite="mid:200910201243.23656.trueg@kde.org" type="cite">
<blockquote type="cite">
<pre wrap="">
I have no time for discussions, please take the input as is.
</pre>
</blockquote>
<pre wrap=""><!---->
:P
</pre>
</blockquote>
well, seems I did have time. ok, back to the next telco now ... 8-]<br>
<br>
best<br>
Leo<br>
<pre class="moz-signature" cols="72">--
_____________________________________________________
Dr. Leo Sauermann <a class="moz-txt-link-freetext" href="http://www.dfki.de/~sauermann">http://www.dfki.de/~sauermann</a>
Deutsches Forschungszentrum fuer
Kuenstliche Intelligenz DFKI GmbH
Trippstadter Strasse 122
P.O. Box 2080 Fon: +43 6991 gnowsis
D-67663 Kaiserslautern Fax: +49 631 20575-102
Germany Mail: <a class="moz-txt-link-abbreviated" href="mailto:leo.sauermann@dfki.de">leo.sauermann@dfki.de</a>
Geschaeftsfuehrung:
Prof.Dr.Dr.h.c.mult. Wolfgang Wahlster (Vorsitzender)
Dr. Walter Olthoff
Vorsitzender des Aufsichtsrats:
Prof. Dr. h.c. Hans A. Aukes
Amtsgericht Kaiserslautern, HRB 2313
_____________________________________________________
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