[mapserver-users] MapCahe question -- Caching the first couple of zoom levels

[thomas bonfort]

James and others,
I have also had requests for this off-list, but am somewhat weary to
implement this. Firstly, this goes against the concept that mapcache
is a *cache*, although I do clearly understand why/when this could be
needed. Secondly, there's a whole lot of logic that treats the
"metatile" problem that would need to be overridden or worked around
in that case (as we would not want to send a full metatile request to
the WMS server, but only the extent for a single tile. This would need
to be accounted for rather early as multiple incoming requests are
synchronised/paused while waiting for the same metatile).
This is an issue that doesn't scratch any of my itches, so I will
probably not be adding it without any incentive, even more so that
there are some workarounds available as pointed out by Andreas and
Armin. I would also add that rather than implementing this
straightforwardly, I would prefer having the possibility of having
multiple caches per tileset, depending on the zoom level, so that e.g.
high zoom level tiles could be stored to a volatile memcache backend
that automatically does the pruning, thus avoiding the metatile issues
completely.

regards,
thomas

On 24 November 2013 16:57, James_in_Utah <James.Evans at hill.af.mil> wrote:
> Hi,
> I'm trying to configure mapcache (from latest dev version of MS4W) and would
> like to cache the first couple of zoom levels of a very large set of USDA
> NAIP imagery.  I've tried using the minzoom and maxzoom tags in the tileset,
> like this:
> <grid restricted_extent="-180 -90 180 90" minzoom="1"
> maxzoom="6">WGS84</grid>
> but once I zoom below the maxzoom value I get no imagery.  I would like it
> to send the request to the source if it is beyond the maxzoom value.  Is
> there a way to do this?
> Thanks,
> James
>
>
>
>
> --
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