I have this idea of using postgis together with a tile renderer for serving my organization with tiled maps. As I believe my data will be partially altered almost on a daily basis it does feel like a performance issue if I have to render the whole cache every night as the changes are quite small but still significant.
Would it be possible to re-render parts of a tile pyramid or a grid in a cache instead of a complete re-rendering?
And have anyone tried to execute this rendering in for example mapnik from inside postgresql/postgis using a database trigger? I believe the first issue would be to determine what tiles are affected and then re-render them specifically.