Re: [thredds] WMS servers side image cache

There is a ehcache.xml spring config file in WEB-INF which looks promising but I don't see anything about WMS in the cache documentation.

http://www.unidata.ucar.edu/projects/THREDDS/tech/reference/ThreddsConfigXMLFile.html#Cache_Locations

My cache directories are essentially empty. Can someone confirm or deny thredds WMS is using or could use ehcache? It would be great if I could use ehcache to cache the data for my tiles (and have them persist) so I can change the image styling on the fly (best of both worlds).



On 05/12/2011 10:36 AM, Guan Wang wrote:
In the original ncWMS package, caching has been considered through Ehcache.

http://www.resc.rdg.ac.uk/trac/ncWMS/browser/trunk/src/java/uk/ac/rdg/resc/n
cwms/cache/TileCache.java

Not sure if this is still kept after the integration with THREDDS.

Guan
-----Original Message-----
From: thredds-bounces@xxxxxxxxxxxxxxxx
[mailto:thredds-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Jay Alder
Sent: Thursday, May 12, 2011 1:09 PM
To: THREDDS Users
Subject: [thredds] WMS servers side image cache

Hi, I'm playing around with using Thredds WMS using a tiling scheme
similar to google maps and I was wondering if there was a way (or
something that could be added in the future) to cache WMS maps from the
thredds servlet? Since I'm using tiles, the requests are identical. I
was thinking thredds would be able to hash (say md5) the request url and
write the image to temporary folder. On the second request thredds would
look in the cache based on the hash, and return the image if its there
otherwise generate a new image.  Thredds would likely need to wipe the
cache on a restart in case the data changed.

Using IDL I wrote some code that downloaded all the tiles at all levels
for a particular dataset, but it took about 12 hours to run and
generated 400,000+ tiles for only one variable. If thredds cached images
it would be a more "on demand" approach rather than trying to pre
generate millions of tiles. In the tiled world, caching would say a lot
of server side processing (especially for high resolution datasets) and
speed up the user experience.

-Jay Alder

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