Popups take long to show up

[nesnoj]

• Up to 15s which is not acceptable.
• ~2s when map data is fully loaded -> maybe related to Ajax 404 with MVTs #139 ?

[henhuy]

We could try to increase gunicorn workers and/or threads.
But this is more or less try and error - so server would be down/up several times while testing
On my machine, popups are fast (500ms max)

[nesnoj]

Now that you fixed #139 the point layers take about 2s 👍 .
The slowest ones are the FF-PV layers: When MVTs are completely loaded, they take 2s as well, otherwise up to 10s (especially if many layers are active at the same time).

BTW, when moving the map view, loading MVT takes quite long due to the large amount of data. As we don't use LODs I could try to reduce feature count and accuracy. Or we could add a spinner..

[henhuy]

Unfortunately, I don't see how to improve speed of popups easily, as:

• view logic cannot be improved (is already fast IMO)
• requests to server cannot be prioritized (i.e. handle popup requests before MVT requests) - this is not possible in django
• precalculating popups and store them in storage client-side would be way too much overhead

Other ideas?
Maybe we could give feedback if popup is loading at least, so that user does not click multiple times...?