In the second interesting item of the week, I return to the fabulous Google Finance chart, which shows the distribution of stock market returns by sector. I wrote about it twice (here and here). In the original post, I saluted the engineers for figuring out the formidable technical issues of turning a live dynamic data stream into a live dynamic graphic but didn't go into details. (Trust me.)
The other night, this chart popped up on my browser.
If someone kept track of each time such a mishap showed up, the tally would probably be 1-5% of the time.
The triple challenge of generating this graphic is the volume of data that needs to be processed, the velocity at which it changes, and the flicker of time from input to output, probably not more than a few minutes. The analysis and charting must be maintained continuously during market hours. For any such projects, the thing to manage is the error rate, and one should be totally thrilled if it's in the range Google engineers have achieved.