How can I speed up Dash in browsers with slow JavaScript engines?

Dash Python
1

I love Dash for its ease of use, but why does it get so unproportionally slow when used in slow browser?

I have a Dash app with four line charts, each with, say, 100 data points. When I access it from another machine with a native Firefox browser it’s certainly fast enough. (Responds time around 1 sec until the whole page is rendered.)

But we will deliver the app to most users in a virtualised desktop environment (like Citrix) and in this environment the JavaScript engine of the Firefox browser is a little slow. So I expect that the page loads a little bit slower (network is the same and pretty fast), but it takes 9 seconds(!!!) until the same page is rendered.

In comparison a page with the same four charts built with Highcharts graphs renders in a native browser in 0.5 secs and via the virtualised browser in under 1 sec - that is less than factor 2 slowdown compared to factor 9 in Dash.

Why is that and what can I do about it in Dash? Back-end caching (Redis, etc) makes obviously no difference.

Thanks for any pointers!

2

Have you looked at the page load times in the dev tools console? It would be worth confirming that it is actually slow page rendering, as opposed to slow request responses, which is often the bottleneck.

3

Thanks @nedned for chiming in.

I just had a look in the browser and it is definitely the page load time, not the request response times.

As said the pages load quick in a native browser, but 9 times slower in a virtualised browser. - Can some of the JavaScrpt processing be cut down?