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<DIV dir=ltr align=left><SPAN class=824443622-01092005><FONT face=Arial
color=#0000ff size=2>I had considered logging before but decided not to because
the volume would be severly large, but as you suggest, I can tweak the
logging to just record intersting stuff.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=824443622-01092005></SPAN><SPAN
class=824443622-01092005><FONT face=Arial color=#0000ff size=2>Another problem I
had was that the the logging has to be thread-safe and non blocking.
</FONT></SPAN><SPAN class=824443622-01092005><FONT face=Arial color=#0000ff
size=2>Any tips there?</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=824443622-01092005><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=824443622-01092005><FONT face=Arial
color=#0000ff size=2>Stacey</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=824443622-01092005><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left>
<HR tabIndex=-1>
</DIV>
<DIV dir=ltr align=left><FONT face=Tahoma size=2><B>From:</B>
delphi-bounces@ns3.123.co.nz [mailto:delphi-bounces@ns3.123.co.nz] <B>On Behalf
Of </B>Dave Jollie<BR><B>Sent:</B> Friday, 2 September 2005 10:24<BR><B>To:</B>
NZ Borland Developers Group - Delphi List<BR><B>Subject:</B> RE: [DUG]
DataSnap/Midas App Server Error<BR></FONT><BR></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">You could create a
logging class. In each important procedure on the server’s RDM, create a
logging instance at the beginning of the procedure. Wrap the procedure in a
try finally, freeing the logging object at the end of the procedure. Within
the try..finally, have a try…except, catching any exception and feeding it to
the logging object. The logging object records to file, the start and end
times of the procedure, any exceptions, etc. In this way you’ll find
procedures that are bottlenecks, procedures that throw exceptions, and any
that never return, for whatever reason.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">To reduce the volume
of your log file, on freeing of the logging object, you could do some tests –
if no exceptions were recorded in the procedure and it didn’t take too long to
execute, then don’t write any info to file – only write to file for exceptions
or very long times. However, then you’d miss any procedure which never
returns. For this you’d need to log a procedure name and time stamp on create
of the logging object.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">You could have an app
server switch to turn logging on and off, so that it’s not going all the time,
but only when indicated from the app server GUI.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">This may help you
find something…<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Dave<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<DIV class=MsoNormal style="TEXT-ALIGN: center" align=center><FONT
face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt">
<HR tabIndex=-1 align=center width="100%" SIZE=2>
</SPAN></FONT></DIV>
<P class=MsoNormal><B><FONT face=Tahoma size=2><SPAN
style="FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT
face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">
delphi-bounces@ns3.123.co.nz [mailto:delphi-bounces@ns3.123.co.nz] <B><SPAN
style="FONT-WEIGHT: bold">On Behalf Of </SPAN></B>Stacey Verner<BR><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Friday, 2 September 2005 9:48
a.m.<BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> NZ Borland
Developers Group - <st1:place w:st="on">Delphi</st1:place> List<BR><B><SPAN
style="FONT-WEIGHT: bold">Subject:</SPAN></B> [DUG] DataSnap/Midas App Server
Error</SPAN></FONT><o:p></o:p></P></DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">We have an DataSnap/Midas app
server which fails randomly.</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">We can't make it happen no matter
how hard we try, but it happens fairly regularly on our production
machine.</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">A little bit of info on the app
and app server:</SPAN></FONT><o:p></o:p></P></DIV>
<UL type=disc>
<LI class=MsoNormal
style="mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l0 level1 lfo1"><FONT
face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">The
applicaiton is a normal database application.</SPAN></FONT><o:p></o:p>
<LI class=MsoNormal
style="mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l0 level1 lfo1"><FONT
face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">The
application also needs to get information from a
settings (metadata) database such as:</SPAN></FONT><o:p></o:p>
<UL type=circle>
<LI class=MsoNormal
style="mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l0 level2 lfo1"><FONT
face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Which
databases they have access to</SPAN></FONT><o:p></o:p>
<LI class=MsoNormal
style="mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l0 level2 lfo1"><FONT
face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">What
permissions they have on the database etc</SPAN></FONT><o:p></o:p>
</LI></UL>
<LI class=MsoNormal
style="mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l0 level1 lfo1"><FONT
face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Instead
of connecting directly to the settings database we use the app server which
shares one database connection between all clients.</SPAN></FONT><o:p></o:p>
<UL type=circle>
<LI class=MsoNormal
style="mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l0 level2 lfo1"><FONT
face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">This
means that there is one database connection for each application instead
of 2 which reduces licencing costs</SPAN></FONT><o:p></o:p> </LI></UL>
<LI class=MsoNormal
style="mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l0 level1 lfo1"><FONT
face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">We use
the borland socket server and a socket connection to connect to the app
server.</SPAN></FONT><o:p></o:p>
<UL type=circle>
<LI class=MsoNormal
style="mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l0 level2 lfo1"><FONT
face=Arial size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">When
we used a normal DCOM connection each client got its own copy of the app
server, so the settings database connection is not shared and in effect
each application had two connections to the
database.</SPAN></FONT><o:p></o:p> </LI></UL></LI></UL>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Sometimes the app server locks up
and the clients can't connect.</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">We have a work around that will
try app servers on other machines if this fails which works OK, but if it
never gets a connection the all sorts of odd things
happen.</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Firstly, does anyone have any
thoughts on this. Debug ideas etc?</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Secondly, when the connection
to the app server fails it takes forever (minutes) to return no matter what I
set the socket connection timeout to.</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Thanks</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Stacey</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<P class=MsoNormal><FONT face="Courier New" size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">Stacey
Verner
Ph: +64-9-4154790<BR>Software
Developer Fax:
+64-9-4154791<BR>
DDI: +64-9-4154797<BR>CJN Technologies Ltd.
Email: </SPAN></FONT><A href="mailto:stacey@cjntech.co.nz"><FONT
face="Courier New" size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">stacey@cjntech.co.nz</SPAN></FONT></A><BR><st1:Street
w:st="on"><st1:address w:st="on"><FONT face="Courier New" size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">PO Box 302-278,
North</SPAN></FONT></st1:address></st1:Street><FONT face="Courier New"
size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'"> Harbour,
<st1:City w:st="on">Auckland</st1:City> 1330, <st1:country-region
w:st="on"><st1:place w:st="on">New
Zealand</st1:place></st1:country-region><BR><st1:Street w:st="on"><st1:address
w:st="on">12 Piermark Drive, North</st1:address></st1:Street> Harbour,
<st1:place w:st="on"><st1:City w:st="on">Auckland</st1:City>,
<st1:country-region w:st="on">New
Zealand</st1:country-region></st1:place><BR>Visit our website at
</SPAN></FONT><A href="http://www.cjntech.co.nz/"><FONT face="Courier New"
size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">http://www.cjntech.co.nz/</SPAN></FONT></A><FONT
face="Courier New" size=2><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">
</SPAN></FONT><o:p></o:p></P>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV></DIV></BLOCKQUOTE></BODY></HTML>