[Monotone-devel] Re: [sqlite] disk locality (and delta storage)

[drh]

Nathaniel Smith <address@hidden> wrote:
> 
> Right now
> we do backwards linear delta chaining, so we always have the latest
> version of everything stored in full, and then it takes O(n) time to
> fetch a version n steps back in history.  While theoretically
> problematic, this actually has caused zero complaints; people in
> practice always check out the latest head... However, it is causing us
> problems when synchronizing databases over the network, because when
> synchronizing you want to send _forward_ deltas. 

Can you store forward deltas for the benefit of netsync, but
also keep a cache of the N most recently accessed files (which
will typically be the ends of the chains) or perhaps just the
latest files in each chain, and thus avoid the O(n) deltas
that would otherwise be required to checkout the head?

--
D. Richard Hipp   <address@hidden>