1. Optimizing Sequences of DB Operations
Problem:
Workflows, query generators, appl programmers all produce sequences of simple steps
Op1 -> Op2 -> Op3… -> OpN
Overhead on each call
Sometimes expensive materialization of intermediate results
Goal:
Merge subsequences into more complex queries
Op123 -> Op45… -> OpN
When can you merge? How much should you merge?

2. Where to do what when in distributed query processing
Problem:
Data-intensive computations over distributed data
Scientific and commercial examples
Heterogeneous environments
Want to spread the work over multiple systems, but
Load on systems varies unpredictably
Costs of shipping data may be prohibitive
Limited use of and lack of mechanisms for function-shipping today
Cost of evaluating more options may be prohibitive
Goal:
Enhance performance of distributed queries
Respond to changing environment