On 6/11/12 11:20 PM, Nick Kew wrote:
On 12 Jun 2012, at 02:49, Leif Hedstrom wrote:
Another option that I've been pondering, which is more suitable for large
contents I think, is to kick off background requests for the full objects. A
plugin that does something like:
Thoughts?
I seem to recollect discussing approaches to caching ranges recently
(was it with you?)
What you outline makes sense where the resource is much bigger than
the requested range, and fetching the whole thing (in a rangeless
request to the backend) would be too much overhead. But to enforce
it on all range requests could be overkill. I wonder if there's a case
for adding a heuristic to examine the client's ranges, and fetch
the whole thing while the client waits UNLESS the number of
bytes the client wants to skip exceeds some threshold - which
then triggers what you describe?
Yeah, I totally agree. There are some potential alternatives here, such as
fixed sized chunking of content perhaps. It's still a difficult problem to
solve optimally for every type of request. Your suggested heuristics
probably is reasonable for many cases, but what is the client asks for the
first 16KB, and we have no idea how long the request is (it could be e.b.
512GB)? Do we defer dealing with it until we have collected enough data to
build an intelligent decision?
Also, blindly caching every Range: request could potentially completely fill
the cache with responses that partially overlap (there are no restrictions
on how the client can form the Range requests :/).
Cheers,
-- leif
