Programmer's Log

Tuesday, October 24, 2006

It has been 14 days since I last updated my blogs. Time sure flies. My schedule was filling with huge amount works and lots of problems on the performance sides of the system. I stopped implementing new requests, passed my tasks to my juniors, and concentrated more on improving the performance of our previous implementation.

We launched 3 sites of our .NET system. For the first week, everything went fine except for the odds information display trouble. The second week of launching, we started running into problems. Everything also started with the odds information display. Our odds cache wasn't stable. In order to relieve the load to the web server and the system itself we implemented a middle layer with .NET Web Services to obtain the odds information. We implemented it in the way that there was a infinite polling mechanism to get the information from the database and kept that information always fresh in the cache of the Web Services. For our problems, our polling mechanism always stopped unexpectedly. Before launching the new 3 sites, I worked around this problem by stopping the IIS to recycle its worker process on IIS schedule. This idea worked fine when we had less sites and the more sites we had problem started showing. The complains that we got from the customer more and more as my 3 sites stayed in the production. I listed down 3 things, I had to solve immediately.

  • Odds Cache -> use .NET Cache Object because it has the automatically expiration parameters for each objects stored in there.

  • Improve the display speed of odds information.

  • Check up our server. It starts to respond really slow on some requests

I tried to improve the odds display first. The solution for this was so much easier than I thought, I just changed the way of calling a function which is used to create our betting slip. Something could surprise people that it had an impact on the rendering engine of Internet Explorer 6.

<span onclick="parent.frameA.buildSlip()">0.98</span>


<span onclick="a();">0.98</span>
<script type="text/javascript">
function a() { parent.frameA.buildSlip();}

It was not just out of no where I made this changes. I went to read some articles about IE having some memory leak issues in its javascript engine. And the part of circular references of register onclick event caught my attention.

I changed the odds cache to the new way using the Cache Object, and did more tunning on our display scripts for my last chance before the management's orders to switch 2 of our sites back to the good old ASP version. My tests showed positive results, deployed new changes to the production was the last thing I did before leaving the office.

On our critical night, our web server drive was filled up with logs files from IIS. I forgot to turn off the logs file. Next morning, my email was full of complains from the operators. :( They should've called me ... As promised with the management, we switched back 2 sites to our old versions.

... and to be continued ...


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