Re: [thredds] WMS servers side image cache

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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