[Gnu-arch-users] Re: RFC: arch protocol, smart server, and tla implementation prototypes

[Chris Gray]

On 31 Jan 2004, Aaron Bentley wrote:
> Jason McCarty wrote:
>
>> Orthogonally, you can make a (client + server time) vs (server
>> diskspace) tradeoff by caching more or fewer summaries on the
>> server, in a hierarchical decomposition. E.g., if a version
>> contains 1024 patches (a nice round number ;-), you can have
>>
>> summary-0-1024 summary-0-512, summary-512-1024 summary-0-256
>> summary-256-512 summary-512-768 summary-768-1024 ...  :
>>
>> So depending on how much disk you're willing to burn, you can bound
>> the number of deltas sent for a given DELTA command to around
>> log2(#patches in version).
>
> You can also implement the caching/composing logic as part of an
> archd proxy.  I can imagine more free-form caching, e.g. server gets
> the following requests: 0-39, 0-32, 0-50, 0-60 After these, server
> retains summary deltas for 0-32, 32-50.  Or is that 0-32, 32-39,
> 39-50?  Or what about 0-39, 39-32, 39-50?
>
> This could get baroque pretty easily, but it would allow lots of
> room for tuning.

I will probably get flamed by some for saying this, but skiplists [1]
do a pretty good job of this without any of that bogosity.

Cheers,
Chris

[1] ftp://ftp.cs.umd.edu/pub/skipLists/skiplists.pdf