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<p class=MsoNormal><span style='color:#1F497D'>I think we encountered this as
well. <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 set up a mirrored server for
multi-user data management access and then push the library package off hours
to the production server which is used for viewing. This allowed us to
utilize the caching for performance on production. The crashes stopped
completely.<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'>Couldn’t figure it out for
the first while.<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'>Kori Maleski<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 lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> mapguide-users-bounces@lists.osgeo.org
[mailto:mapguide-users-bounces@lists.osgeo.org] <b>On Behalf Of </b>Haris
Kurtagic<br>
<b>Sent:</b> May-19-09 4:59 AM<br>
<b>To:</b> MapGuide Users Mail List<br>
<b>Cc:</b> fdo-users@lists.osgeo.org<br>
<b>Subject:</b> [mapguide-users] finally<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New";
color:black'>Finally we found what was causing MapGuide server to crash while
reading data from MapGuide.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New";
color:black'>It took us lot of energy and time.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New";
color:black'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New";
color:black'>Problem will appear in multiuser environment with concurent access
when you are using provider which is per command threaded or sharing (caching)
FDO schema accross multiple connections.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New";
color:black'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New";
color:black'>Issue is in function: MgServerGetFeatures</span><span lang=EN-US
style='font-size:10.0pt;font-family:"Courier New"'>::<span style='color:black'>SerializeToXml</span>(<span
style='color:black'>FdoClassDefinition</span>* <span style='color:black'>classDef</span>)
which will in order to serialize class to xml remove that class from schema,
put it to temporary schema serialize and return class to original schema. While
doing this if another thread goes to execute, problem starts.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>Workaround
is to set provider to per connection threaded or not cache schema at all, and
both comes with perfomance penalties.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>I
think that few things are important in this case beside the obvious issue. One
of them is missing constant pointers in FDO API. Schema returned from provider
shouldn't be allowed to be changed by fdo clients. That is something were
problems appeared already.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>Also,
I think that serialization using XML is not right way to go. XML we could use
to serialize data to end-user not for internal MG processes.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>Haris</span><span
lang=EN-US><o:p></o:p></span></p>
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