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<p class="MsoNormal">Hi Marten<br>
<br>
What about System>>millisecondsSinceTransactionBoundary?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Lourens<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> Glass <glass-bounces@lists.gemtalksystems.com> <b>
On Behalf Of </b>Marten Feldtmann via Glass<br>
<b>Sent:</b> Tuesday, 23 August 2022 09:31<br>
<b>To:</b> via Glass <glass@lists.gemtalksystems.com><br>
<b>Subject:</b> [Glass] How to solve this problem - concurrency on one field/attribute<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><strong><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black">Please note this email originated from external. Please treat with caution.</span></strong><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black"><o:p></o:p></span></p>
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<p class="MsoNormal">I've face a problem for years now using Gemstone/S and I did several attempts to solve this, but I would like to ask, if there is a hidden trick to get rid of concurrency in this case using Gemstone/s.
<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Think about a session object holding an attribute with a timestamp - a timestamp, where the last successful commit has been done in this session. Its a rough index about how the session hasn't done anything (regarding the read-only user
case). <o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">This session object is shared in a Javascript ui frontend-application (actually the gop to the session) - and now whenever this ui calls an API function on the server (resulting in a commit), the session object in the server gets updated.
But if the UI now opens several windows and would like to do sevral independent stuff with the same session in a concurrency way - you will notice, that the API calls might fail - due to concurrency of updating the same timestamp from different "logical"
threads. <o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">How can this be solved in Gemstone/S ? Retry of the transaction just due to this field might be pretty cost intensive.
<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">How did I try to solve that in the past ? <o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">a) I added an update object in a work queue and and independent topaz process worked on that work queue
<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">In a newer attempt I introduced RabbitMQ in our solutions and use RabbitMQ for holding the information formerly stored in the work queue in Gemstone/S and now the topaz process receives information from RabbitMQ and updates the data in
an optimized way. The good thing here is, that I get session updates in an transaction with or without commit.
<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Any ideas ? <o:p></o:p></p>
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