Re: [squid-users] StoreID and concurrency?

On 7/06/2013 3:24 a.m., Eliezer Croitoru wrote:
> On 6/6/2013 4:25 PM, csn233 wrote:
>> On Wed, Jun 5, 2013 at 11:57 PM, Eliezer Croitoru
>> <eliezer_at_ngtech.co.il> wrote:
>>> StoreID is not related directly to cache_dir so it's not suppose to
>>> affect
>>> dirty cache_dir.
>>
>> StoreID uses the output from the helper as the key to store the cached
>> copy in cache_dir, does it not? So if the helper generates one key for
>> the video and a *different* key for the same video next time (if I
>> change the helper output), it will lead to inconsistency for that same
>> video, will it not? Particularly relevant to YT which splits a video
>> into parts (ranges), where each part gets its own key. So if I change
>> the key halfway while the video is playing, things get confusing.
> No it dosnt matter the only *thing* that will happen is that the two
> videos will be served but not from cache.

Small correction. The already underway video will still be served from
cache location where it was found. The new one will be served as a MISS
and stored in the new location.

NP: This is identical to how a cached object which expires between one
fetch and another is handled by Squid. Expiry is the only difference as
the "old" video object is likely still fresh in terms of HTTP and will
stick around wasting space until the cache replacement policy (garbage
collection) decides it has been unused long enough to erase.

Amos
Received on Fri Jun 07 2013 - 05:46:56 MDT