[mapserver-users] MapCache: cache some zoom levels, proxy others?

[thomas bonfort]

> Out of curiosity, can I assume that my other idea, about proxying some zoom
> levels directly to WMS and caching others, is unrealistic?

not unrealistic, but not implemented

--
thomas

>
> paul
>
>
> On 10/28/15 9:36 AM, thomas bonfort wrote:
>>
>> Paul,
>>
>> Are you using metatiling? That would substantially reduce the number
>> of requests mapcache does to mapserver.
>>
>> You also have the
>> <mapcache>
>> ...
>>     <threaded_fetching>true</threaded_fetching>
>> </mapcache>
>> option, that lets mapcache launch mapserver requests in parallel
>> instead of sequentially (YMMV, this option isn't very tested)
>>
>> --
>> thomas
>>
>> On 28 October 2015 at 16:20, Paul Madden <pmadden at nsidc.org> wrote:
>>>
>>> I am working with a web application that makes WMS queries to MapCache.
>>> The application supports zoom levels 0 through 13, and I have used
>>> mapcache_seed to seed the cache through level 10. The deeper levels take so
>>> long to seed that I am considering stopping at level 10 and letting MapCache
>>> / MapServer produce deeper levels on demand, as users visit them. The
>>> problem I'm facing is that, as far as I can tell, MapCache requests tiles
>>> from MapServer serially, then stitches together the required image from
>>> these tiles, when it receives a request for an uncached level. In one test,
>>> 34 separate tiles were requested from MapServer, one at a time, and it took
>>> ~30 seconds to render the final image.
>>>
>>> I'm wondering whether there is a way to configure MapCache to
>>> cache/provide a defined set of zoom levels, and to proxy requests at other
>>> zoom levels directly to MapServer. I tried setting minzoom and maxzoom on my
>>> <grid> in mapcache.xml to "0 10". I tried adding a proxy for my cached
>>> layer, hoping that MapCache would redirect requests for unsupported zoom
>>> levels to MapServer (I have proxies in place for other, completely uncached
>>> layers, and those work fine). I tried copying/renaming the
>>> GoogleMapsCompatible grid definition into my mapcache.xml and removing from
>>> <resolutions> zoom levels I don't want MapCache to cache. So far, these
>>> attempts apparently just prevent MapCache from serving the deeper layers at
>>> all.
>>>
>>> Any thoughts on how I might address this issue? It might also help if
>>> MapCache would make concurrent requests for tiles at uncached levels, but I
>>> have no idea if this is feasible. And it would be nice to be able to let
>>> MapServer handle some zoom levels directly in any case.
>>>
>>> Thanks in advance for any ideas.
>>>
>>> Paul Madden
>>> National Snow and Ice Data Center
>>> _______________________________________________
>>> mapserver-users mailing list
>>> mapserver-users at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>
>
> _______________________________________________
> mapserver-users mailing list
> mapserver-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/mapserver-users