[OSM-dev] Planet change tile expiry list service

Andy Allan gravitystorm at gmail.com
Thu Sep 1 09:25:27 UTC 2016


On 1 September 2016 at 09:25, Yves <yvecai at gmail.com> wrote:
> Along with minutely diffs, I wonder if expired tiles lists would be
> something to be shared: this is something each tile server is doing by
> itself by now, and seems a waste in ressources.

It's not really something that should be relied on, since there's no
"one true list" of expired tiles. For example, the osm.org tileservers
ignore relation expiry entirely. Other servers might expire relations
only when certain tags are changed (little point in expiring all of
germany when an unrendered tag on an admin boundary changes). Some
tileservers use the osm2pgsql output. With large polygons, only the
exterior is expired, but  different operators will have different
ideas as to how large a "large" polygon is, or they may want to expire
the interior too.

Or to put it a different way - which list would you like? The one
generated by osm2pgsql, or the one generated by
https://github.com/openstreetmap/chef/blob/6db231309db4c58f4264beab8a72fd46fdd0d01d/cookbooks/tile/files/default/ruby/expire.rb
? Which is "right"?

Thanks,
Andy



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