Desirable Properties of information gathering plans
Source-complete: no other plan returns more information using the available sources
- Different from the traditional “query equivalence” requirement
Source-minimal: a plan for which no information source can be removed, yet the plan returns the same answer.
Access-cost minimal: a plan which reduces the number of separate accesses to individual sources
Bandwidth-minimal: a plan that, when executed, transfers the smallest amount of data over the network yet is still source complete