On 31/08/12 22:36, Ariel T. Glenn wrote:
So there are some things we could change:
1. We could generate and keep only certain sizes, tossing the rest.
2. We could keep *nothing*, scaling all media as required.
3. We could have a cron job that was clever about tossing thumbs every
day (not sure how easy it would be to be clever).
I'll go for option 4. You can't delete the images from the backend
while they are still in Squid, because then they would not be purged
when the image is updated or action=purge is requested. In fact, that
is one of only two reasons for the existence of the backend thumbnail
store on Wikimedia. The thumbnail backend could be replaced by a text
file that stores a list of thumbnail filenames which were sent to
Squid within a window equivalent to the expiry time sent in the
The other reason for the existence of the backend thumbnail store is
to transport images from the thumbnail scalers to the 404 handler. For
that purpose, the image only needs to exist in the backend for a few
seconds. It could be replaced by a better 404 handler, that sends
thumbnails directly by HTTP. Maybe the Swift one does that already.
-- Tim Starling