[QGIS-Developer] QGIS WMS provider firing too many requests !?

[Richard Duivenvoorde]

On 2/13/21 8:01 PM, pathmapper wrote:
> Hi,
> 
> here's a related thread (i.e. xyz tiles, but I guess it's also valid vor wms):
> https://github.com/qgis/QGIS/issues/34813
> 
> Some quotes:
> "QGIS renders the surrounding areas in a background job to make subsequent pan actions faster. Therefore it sends more tile requests than necessary for the current map extent."
> 
> "Btw, we now have the code in place to fine-tune prefetching behavior for all raster layers on a per-layer basis, for now I just blacklisted osm tiles."
> 
> It sounds like the plan is to make the prefetching behavior configurable via QGIS settings.

See https://github.com/qgis/QGIS/pull/41832 to prevent prefetching for true WMS's...

Now I like to have some input indeed making prefetching behaviour more configurable:

- where to put a checkbox/setting about prefetching tiles (global raster, or per wms service or just global, or a hidden setting)?
- what to make default (with or without prefetching...?)

My first idea:
- add a checkbox "Prefetch surrounding WMS(T) images" in the WMS/WMTS Connection dialog in the 'WMS/WMTS Options' section; default FALSE (unless see below)
- In General Options / Network / Cache Settings add a  tab or just a checkbox with "Default prefetch WMS(T) images" (defaulting to FALSE, but if enabled the above mentioned checkbox will always be enabled too)
- also make this an option in the provider uri 

Input?

Regards,

Richard Duivenvoorde