> Okay... how long does a round-trip cost? With a protocol that wasn't made for the purpose (such as HTTP) and all that HTML to "render" (not to mention javascript that's required for even the most trivial issues) - way too long.
> Considering that usability guidelines generally permit ~100ms for > direct interaction, That's "generous". A proficient user with a responsive application can easily outpace that. 100ms is definitely a noticeable lag. Even I feel that and I don't use touch-typing to use the GUI. 50ms might not be noticeable, but I don't have the skills myself to test that. > (Magento, a PHP-based online shopping cart system, took the better > part of a second - something in the order of 700-800ms > - to add a single item. And that on reasonable hardware, not a > dedicated server but my test box was certainly not trash.) That's not a question of hardware. Just like with MS (Not Responding). > That's the entire round-trip cost. The queries from Sikorsky to > Yosemite involve three computers (the client, the server, and the file > server), and is completed in under 30 milliseconds. I am talking about applications that actually do something. In my case, database applications. A PostgreSQL transaction is supposed to take at most 25ms to complete (anything above is generally considered an issue that needs to be solved, such as bad SQL), *server-side*. That leaves you another 25ms for the entire network protocol (the pgsql protocol, whatever it is, was designed for the purpose, unlike HTTP) *and* the client-side application logic, including the GUI "rendering". Qt is already quite sluggish sometimes, don't know why. GTK and wxPython "feel" swifter, at least on an actual *operating* system. MS (Not Responding) is definitely incapable to allow applications anything remotely close to "responsiveness". Minute-long lockups with frozen cursor are "normal". > That still gives you 70 milliseconds to render the page to the user, Forget that. 25ms for client-server (pgsql) network protocol, client-side application logic *and* GUI. With a "web" application that would have to include "application server"-side application logic, *and* generation of HTML (and javascript), *and* HTTP protocol *and* HTML "rendering" *and* client-side javascript. Won't work. Sincerely, Wolfgang -- http://mail.python.org/mailman/listinfo/python-list
