The HalSail server gets very busy on weekends when there are lots of regattas. There were a couple of occasions last year when it slowed to a crawl, due to hundreds of boats finishing at about the same time and entire crews using their mobiles to see how they had done.
The immediate availability of new results is one of the big advantages of HalSail, so I have been working hard to build more resilience into the system. I have done that by storing results on other computers on the web, as well as the HalSail server. So when people ask for the results of a particular series, the request goes to one of the other computers in the first instance. That computer gets its results from HalSail once every five minutes. This is known as caching.
The net result is that HalSail should be much more resistant to high work loads, but that results may be up to five minutes late. In other words, if a race officer updates the results of a race, those results may not filter through to sailors on their mobiles for up to five minutes. That seems to me to be a reasonable compromise between speed and reliability.
A race officer who is logged in can use the result editing screens to see results. They will not be cached, so what the RO sees is the latest version.