Holger Jaekel wrote: > Hi everyone, > > the module org.geotools.tile currently has an implementation for > accessing the NASA World Wind server and an implementation of a > SimpleTileCache, which caches only the result of the last query. > > We would like to add support for WMS-C [1]. Server implementations are > available from MetaCarta [2] or from GeoWebCache [3]. > > Additionally we want to create at least two tile cache implementations > (MemoryTileCache and DiskTileCache). It should be possible to configure > the size of the cache (number of tiles to be cached) and to plug-in a > cache algorithm like Least Recently Used, Least Frequently Used, or > maybe Adaptive Replacement Cache. Caches can be used in a cache > hierarchy. > Holger Jaekel wrote: > Hi everyone, > > the module org.geotools.tile currently has an implementation for > accessing the NASA World Wind server and an implementation of a > SimpleTileCache, which caches only the result of the last query. > > We would like to add support for WMS-C [1]. Server implementations are > available from MetaCarta [2] or from GeoWebCache [3]. > > Additionally we want to create at least two tile cache implementations > (MemoryTileCache and DiskTileCache). It should be possible to configure > the size of the cache (number of tiles to be cached) and to plug-in a > cache algorithm like Least Recently Used, Least Frequently Used, or > maybe Adaptive Replacement Cache. Caches can be used in a cache > hierarchy. > (I work on GeoWebCache)
Note that if your machine has enough RAM, then most modern operating systems will automatically turn a disk cache into a very fast memory cache with an efficient LRU, for free. If you're using a filesystem then you need one without too much overhead (auditing etc) and a good implementation for file lookups. Ext3 in new distributions uses a btree, combined with "noatime" you get something pretty fast. You can obviously go much faster (and reduce OS dependence) if you can stuff it all into one big file with an efficient lookup mechanism. If you want to read about how to create very fast caches I recommend looking at http://varnish.projects.linpro.no/ Lots of it is not applicable to what you are trying to do, but they have given the interaction with the OS a great deal of thought and I think that is more important than figuring out what should be stored in memory. Note that GeoWebCache still has a number of bugs and doesn't provide the required capabilities document, but it'll get there fairly soon, I hope. -Arne > Are there currently and other activities in that area that we should be > aware of? Are there any ideas oder suggestions from you? > > Regards, > Holger > > > [1] http://wiki.osgeo.org/wiki/WMS_Tiling_Client_Recommendation > [2] http://www.tilecache.org/ > [3] http://geowebcache.org/ > > --- > Holger Jaekel > phone: +49 (89) 121528-75 mailto:[EMAIL PROTECTED] > fax: +49 (89) 121528-79 http://www.gaf.de > GAF AG Arnulfstr. 197 80634 Muenchen Germany > > Vorstand: Dr. Peter Volk, Aufsichtsratsvorsitzender: Marcello Maranesi > > Amtsgericht Muenchen HRB 140 509, Firmensitz: Muenchen > > > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Geotools-devel mailing list > Geotools-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/geotools-devel > > !DSPAM:4038,47c7e0da107595219720167! > > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Geotools-devel mailing list Geotools-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-devel
