David Earl wrote: > > So what's going on? If the cache is empty, is the server really serving > an old tile? Is there some proxying going on somewhere (there's no > explicit proxies)? Why is it random which tiles update? > Yes, there is a server side proxy in-between the tileserver to reduce load on the main timeserver and it can have these slightly odd updating behaviors. As the proxy servers don't use an explicit expiry mechanism for when the rendering server has rendered a new tile, it can serve old tiles if it was caching them before the rendering.
Which tiles update depend on when they were last viewed by anyone, which proxy it goes through, when the tile was previously rendered and if the tile is still in cache. mod_tile uses a combination of etag-headers based on the md5 of a tile and on expiry-headers with a prediction of how long mod_tile guesses the tile might not be updated for and thus can be considered fresh by a proxy without rechecking for modifications. Kai -- View this message in context: http://gis.638310.n2.nabble.com/Map-tiles-in-Chrome-tp6917001p6922674.html Sent from the General Discussion mailing list archive at Nabble.com. _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
