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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">But is this not a bad pattern?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The way I handle this is:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Take incoming message<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Propagate to my own queue, then handle it from there.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">As a result, I am not even “cracking” messages in the receiving thread, but later in the processing handler. This one runs, as I said, in a separate thread
with an in memory queue ;)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Yes, it COULD fill up, but that would require a large amount of messages ;)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thomas<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<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""> quickfixn-bounces@lists.quickfixn.com [mailto:quickfixn-bounces@lists.quickfixn.com]
<b>On Behalf Of </b>Matt Wood<br>
<b>Sent:</b> 08 June 2012 16:31<br>
<b>To:</b> Mailing list for QuickFIX/n<br>
<b>Subject:</b> Re: {{Quickfixn}} Socket Deadlock Issue<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Christian,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi, I'm another user and recent contributor of the quickfix/n library. I have encountered this in a related fashion (but triggered differently) and agree with your final paragraph:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">"However, in the long run, we may need / want to have distinct receive and process threads. As it is, the same thread will block while calling into the actual FIX application for message processing. Should that processing take a long time
or involve, for whatever reason, sending a large number of messages ... then we could wind up in a similar problem. Say the FIX application took 2 minutes to process some particular received message (in a blocking synchronous way) ... and during that 2 minutes,
the other side of the FIX connection had sent enough messages to fill up it's socket buffer and block. By ensuring that message processing is in a separate thread from the socket reading then we will guarantee (in a far better way) that our socket should never
wind up inadvertently blocking the other side. "<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Some of my processing (mainly database updates) of messages causes a pile up when receiving an exceptionally large number of messages in a short time period. Specifically, I get this at the end of the day (around 5pm) when the system we're
connected to propagates a series of IOI messages to mark market offerings as being unavailable (due to traders being forcibly logged out of the system for the day). The pile up manifests itself as "TCP ZeroWindow" messages to be sent from our side telling
the foreign system to delay sending further messages. Eventually the delayed TCP messages are sent and received as our system catches up, but are rejected by our fix engine due to the fact that the messages exceed the configured latency (2 minutes!). Of course
there is much I can do to alleviate this particular problem, such as creating some sort of queue and threading at a higher place in the app. However, I do feel that a distinct processing thread makes sense and would benefit the overall robustness of the application.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">-Matt Wood<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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