algebraic query optimizer [Draft]

[salmans]

The query optimizer should be extendable, making it possible to add more optimization rules. Challenges arise due to losing type information when composing expressions, which can be dealt with as follows:

• Apply query optimization when constructing expressions (e.g., using an expression builder). This approach would allow only for optimizing the query at the current level of the expression tree.
• Expressions may be enhanced with metadata that contains a Tuple-type-free expression tree.