Manual update of one or more lists will cause the most recent version
of these lists to be fetched from the "origin" server, and since the
lists from "origin" servers cannot be updated through differential
update, the lists will be subsequently updated according to their
`Expires` directive.
When the lists are auto-updated, the "CDN" servers will be used,
and as a result the lists will start to be updated trhough
differential updates every 6-hour (currently).
Thus it is recommended and optimal to let the lists auto-update,
since you will benefit from a much shorter delay to get up-to-date
lists (i.e. every 6-hour instead of every 6-day).
You can force the auto-updater to fetch all the lists by clicking
"Purge all caches", then restart uBO without clicking "Update".
This will cause uBO to perform an emergency auto-update at restart
time, after which you will have all the lists which are candidates
for differential update.
The "Update now" button in the "Support" pane will also cause lists
to be fetched from their "origin" server.
Related discussion:
https://github.com/ameshkov/diffupdates
The benefits of diff-patching filter lists is much shorter update
schedule and significantly less bandwidth consumed.
At the moment, only default filter lists are subject to be
diff-patched.
External filter lists can make their lists diff-patchable by
following the specification link above.
Only filter lists fetched by the auto-updater are candidate for
diff-patching.
Forcing a manual update of the filter lists will prevent the
diff-patcher from kicking in until one or more lists are
auto-updated.
Some back-of-the-envelop calculations regarding the load on free
CDN solutions used by uBO to distribute its own filter lists:
Currently, for each CDN (with lists updating after days):
~560 M req/month, ~78 TB/month
With diff-patching lists on a 6-hour schedule:
~390 M req/month, 1 TB/month
Those estimates were done according to statistics shown by
jsDelivr, which is one of 4 CDNs picked randomly when a list
updates:
https://www.jsdelivr.com/package/gh/uBlockOrigin/uAssetsCDN?tab=stats
I worked through some of the websites listed in the google-ima shim
script issue[1], to see what was going wrong. It turned out the
addEventListener method supports an optional context Object, which is
bound to the listener if provided. Some websites make use of that,
and then break when `this` is not bound correctly when events are
dispatched.
See also https://github.com/duckduckgo/tracker-surrogates/pull/24
1 - https://github.com/uBlockOrigin/uBlock-issues/issues/2265
