Thomas,

Our server is behind a firewall, but anyways here is some of the information 
that I can share which might help.

Server: New Quad Core Xeon, 20 GB ram, 1Tb storage free, RAID 5 
Tiles: jpeg (source, cache format, and format used in assembling tiles)  
Grid:  County Coordinates, 256*256, extent matches the extent of the client 
application

Zoom Level, Resolution, Approximate Scale (Res*12*72)
0, 1024, 1:884736  (region)
1, 512 , 1:442368
2, 256 , 1:221184  (county wide)
3, 128 , 1:110592
4, 64 , 1:55296
5, 32 , 1:27648
6, 16 , 1:13824
7, 8 , 1:6912   
8, 4 , 1:3456
9, 2 , 1:1728
10, 1 , 1:864
11, 0.5 , 1:432  (0.5 feet matches the size of the imagery)

Unscientific speed results for various assemble types:

Source wms server: 400-800 ms
1:6912 (resolution matching cache, area cached) 4-50 ms
1:6912 (resolution matching cache, area not cached) Cache hits are around 
.470-1.4 seconds 
1:7000 (forward to wms server) 500-800 ms
1:7000 (assemble from cache on an area already cached) 1-12 seconds (panning 
small amounts is quicker, zooming in our out takes a while)
1:7000 (assemble from cache on an area not already cached) 2-14 seconds 

Thanks

Mark Volz
GIS Specialist

-----Original Message-----
From: thomas bonfort [mailto:[email protected]] 
Sent: Tuesday, June 12, 2012 5:27 AM
To: Mark Volz
Cc: MapserverList OSGEO
Subject: Re: [mapserver-users] mapcache - transparency, surrounding area color, 
performance when assembling images (pink tiles)

(please stay on list, you answers can help others facing the same issue)

On Mon, Jun 11, 2012 at 9:26 PM, Mark Volz <[email protected]> wrote:
> Thomas,
>
> It turns out that most of my problems were when <full_wms>assemble</full_wms> 
> was set...  apparently it defaults to jpeg when mapcache has to assemble, 
> which was causing problems with my png caches.  I experimented with changing 
> the default to PNG.
>
> I think my resolutions are set (somewhat) appropriately, for testing I am 
> using resolutions of 1024 512 256 128 64 32 16 8 4 2 1.0 and .5.  when I am 
> browsing at one of these resolutions mapcache is very fast.  It just seems 
> that mapcache is slow when I am using a resolution that is slightly off of 
> one of these.  Anyways, I just turned  forward on 
> <full_wms>forward</full_wms>, which seems to be okay.

Slightly off is expected to be a bit slower, but not very noticeably so.  
Please to try again with some higher resolutions configured (the disk space 
overhead for those will be negligeable), mapcache assembling should be at least 
as fast as a normal wms server if it is allowed to hit a correctly configured 
grid resolution. For reference, the classical mercator grid has 7 higher 
resolutions than what you have configured, which will help for requests 
covering approximately state/country scaled getmaps.
Can you also provide the full url for a getmap request that exhibits this 
behavior, along with timings comparing "assemble" and "forward"
modes.

regards,
thomas



>
> Thank you for all your help!
>
>
> Mark Volz
> GIS Specialist
>
> -----Original Message-----
> From: thomas bonfort [mailto:[email protected]]
> Sent: Monday, June 11, 2012 9:47 AM
> To: Mark Volz
> Cc: [email protected]
> Subject: Re: [mapserver-users] mapcache - transparency, surrounding 
> area color, performance when assembling images (pink tiles)
>
> On Mon, Jun 11, 2012 at 4:32 PM, Mark Volz <[email protected]> wrote:
>> Hello,
>>
>> First,  I am having trouble figuring out how to get transparency to 
>> work in mapcache when using a Mapserver/WMS source.  Does anyone have 
>> an example of how to store a transparent mapcache with a Mapserver wms 
>> source?
>
> make the tileset reference a png format, not a jpeg one.
>
>>
>> Next,  The color of my cache is fine, however the surrounding area 
>> outside of the extent of the cache is black.  Can that be changed to 
>> white, or transparent?
>
> same as previously, configure the wms service create png not jpeg 
> <service type="wms" enabled="true">
>      ...
>      <format>PNG</format>
> </service>
>
>
>>
>> Third,  Mapcache seems really slow when it needs to assemble images.
>> I am getting plenty of pink screens, and the response time is usually 
>> greater than 5 seconds.  Mapcache is much faster when I use 
>> <full_wms>forward</full_wms>, so I know the problem is not the source wms.
>> Does anyone have an idea as to why the performance is poor when 
>> assembling images?
> I suspect you have defined a <grid> who's resolutions aren't of the same 
> order of magnitude as the resolution of the getmap requests, i.e.
> when creating the result image, mapcache has to decompress and resample a 
> very high number of tile images. Try adding a couple of higher resolution 
> entries to the beginning of your <resolutions> array.
>
> --
> thomas
>
>>
>> Thank You
>>
>> Mark Volz
>> GIS Specialist
>>
>>
>>
>>
>> _______________________________________________
>> mapserver-users mailing list
>> [email protected]
>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>
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