Re: Is Diff/Delta Cache Digest Implemented ?

On Mon, 9 Apr 2001, ªL­^¶W wrote:

> Hello Alex:
>
> I am trying to write Diff/Delta Cache Digest
> and now I run into some problem.
>
> I declare an "diff_digest" to store the Diff/Delta Cache Digest.
> but I don't know how to transfer it to peer proxy server.

You will need to design a protocol (possibly on top of HTTP) to
specify various diff properties and to identify the versions of the
digests that the diff is generated from. You may also add features
such as peers telling each-other what digest versions they have so
that an appropriate diff can be sent. Merging two sequential diffs is
also an attractive possibility.

Make sure you read "Subject: Cache Digest Diffs" and related threads
on squid-dev mailing list! A few diff-ing algorithms have been
discussed and compared there.
 
> I try to use the URL
> http://140.112.30.139:3128/squid-internal-periodic/diff_digest
> But I don't think it is good because diff_digest is not periodic object.
> what kind of object should I use ?? squid-internal-static ??

I think a digest diff is a periodic object (because it is generated
from time to time, just like a digest), but I also think it would be
much better if you allow for several diffs to be stored (so your
naming and indexing scheme will have to be more creative than just
"diff_digest"). Maybe something like
        /squid-internal-periodic/store_digest_diffs/index
        /squid-internal-periodic/store_digest_diffs/v1_v2
        /squid-internal-periodic/store_digest_diffs/v2_v3
        /squid-internal-periodic/store_digest_diffs/v3_v4
... where the number of versions to keep is a configuration
parameter; but I have not given it much thought...

HTH,

Alex.
Received on Mon Apr 09 2001 - 09:01:12 MDT