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<p class=MsoNormal><span style='color:#1F497D'>Ok, I read that .h many times
:)<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>I would appreciate if you can
help me to understand and discuss why sdf provider is not </span>FdoThreadCapability_PerCommandThreaded.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Thank you,<o:p></o:p></p>
<p class=MsoNormal>Haris<span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> fdo-internals-bounces@lists.osgeo.org
[mailto:fdo-internals-bounces@lists.osgeo.org] <b>On Behalf Of </b>Badreddine
Karoui<br>
<b>Sent:</b> Wednesday, August 13, 2008 10:14 PM<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> RE: [fdo-internals] RE: SDF feature reader <o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='color:#1F497D'>The free threaded provider would
use FdoThreadCapability_MultiThreaded defined in <a
href="https://svn.osgeo.org/fdo/trunk/Fdo/Unmanaged/Inc/Fdo/Connections/Capabilities/ThreadCapability.h">https://svn.osgeo.org/fdo/trunk/Fdo/Unmanaged/Inc/Fdo/Connections/Capabilities/ThreadCapability.h</a><o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>The SDF provider is returning
FdoThreadCapability_PerConnectionThreaded. <o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>I had a quick look and I can see
that the SDFSimpleFeatureReader::GetGeometry(FdoString*, FdoInt32*) is returing
the pointer from the internal buffer. This may have been done to avoid paying
the penalty of copying the geometry. The second oveload, GetGeometry(FdoString*)
is returing a copy and should not have the same issue. <o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>We may have to be extra carefull
in case we decide to fix this issue to make sure the reader performance is not
impacted. <o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Badreddine<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
fdo-internals-bounces@lists.osgeo.org [mailto:fdo-internals-bounces@lists.osgeo.org]
<b>On Behalf Of </b>Haris Kurtagic<br>
<b>Sent:</b> Wednesday, August 13, 2008 3:12 PM<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> RE: [fdo-internals] RE: SDF feature reader <o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='color:#1F497D'>it looks that feature readers
are sharing same sqlite cursor with one data buffer. (BTW:
Application is sending this readers to be used by another app so it is not able
to create new buffers)<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Hm, you have lost me in this
threading namings :)<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Same SDF connection can’t be
shared across threads, right ? ( I thought that as thread safe )<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>I would like to understand
reasons for that behavior and if there are rooms for improvements.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Sqlite connection can be shared
between threads.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Thank you,<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Haris<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
fdo-internals-bounces@lists.osgeo.org
[mailto:fdo-internals-bounces@lists.osgeo.org] <b>On Behalf Of </b>Badreddine
Karoui<br>
<b>Sent:</b> Wednesday, August 13, 2008 8:36 PM<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> RE: [fdo-internals] RE: SDF feature reader <o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='color:#1F497D'>It was not obvious that the
readers were on the same thread. In that case it’s a defect. Make sure to copy
the geometry before ReadNext is called. It’s possible the second
reader(ReadNext) is invalidating the geometry.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>The SDF provider is thread safe
but not free threaded, it’s per-connection threaded.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Badreddine<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
fdo-internals-bounces@lists.osgeo.org
[mailto:fdo-internals-bounces@lists.osgeo.org] <b>On Behalf Of </b>Haris
Kurtagic<br>
<b>Sent:</b> Wednesday, August 13, 2008 2:39 PM<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> RE: [fdo-internals] RE: SDF feature reader <o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='color:#1F497D'>I was saying for two
feature readers inside same thread will result in error.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Also, i would like to understand
why SDF provider is not thread safe.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Haris<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'> <o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
fdo-internals-bounces@lists.osgeo.org [mailto:fdo-internals-bounces@lists.osgeo.org]
<b>On Behalf Of </b>Badreddine Karoui<br>
<b>Sent:</b> Wednesday, August 13, 2008 8:18 PM<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> [fdo-internals] RE: SDF feature reader <o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='color:#1F497D'>The SDF provider is per
connection threaded which means only one thread can access a reader at a time.
You can have many threads using their own connections/readers at the same time.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Badreddine<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
fdo-internals-bounces@lists.osgeo.org
[mailto:fdo-internals-bounces@lists.osgeo.org] <b>On Behalf Of </b>Haris
Kurtagic<br>
<b>Sent:</b> Wednesday, August 13, 2008 2:29 PM<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> [fdo-internals] SDF feature reader <o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Hi,<o:p></o:p></p>
<p class=MsoNormal>I have issue when when more than one feature reader is
created against same SDF connection<o:p></o:p></p>
<p class=MsoNormal>It looks like same buffer ( created by sqlite cursor ) is
shared betwean feature readers.<o:p></o:p></p>
<p class=MsoNormal>This will cause that data returned from feature reader with
function GetGeometry will be corrupted when another reader is used.<o:p></o:p></p>
<p class=MsoNormal>Is this a bug or I am not looking into it correctly ?<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I would like to be able to use multi thread access to sqlite
database.<o:p></o:p></p>
<p class=MsoNormal>If I am right, SDF provider is not “thread safe” ? if so,
what are main reasons for it ?<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Thank you,<o:p></o:p></p>
<p class=MsoNormal>Haris<o:p></o:p></p>
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