[Cosmo-dev] simplifying eimml

[Phillip J. Eby]

At 10:47 AM 12/1/2006 -0800, Morgen Sagen wrote:
>Phillip, correct me if I'm wrong, but does the grouping-by-item
>requirement go away when we truly start sending diffs back and forth
>and not always send complete sets of records?

Not really.  The requirement is based on the peculiarities of how our 
"baseline" storage will work currently.  If we could afford to load the 
whole baseline into memory or had a fast indexing mechanism based on record 
keys (e.g. if we were using a relational back-end), then the requirement 
would go away.

That is, even if Cosmo and Chandler were sending true diffs, it's still 
necessary for Chandler to match the incoming diffs against the previous 
baseline record set - which means the baseline record set has to be either 
in-memory or indexed by record keys.  Using the item "envelopes" allows us 
to load only a subset of the baseline records at any one point in time.