How to evaluate a tree of RA operators?
computer science
Description
Query evaluation
• How to evaluate a tree of RA operators? – Logical and physical optimization (there are many interactions!) – Query evaluation plan is the result
• Logical optimization
Searching for logically equivalent query expressions
To determine the cost of a query we need to have physical QEP
Heuristics without the exact QEPs? (size of result ~ QEP?)
• Physical optimization
Searching for optimal mathods for evaluationg RA operators
Physical optimization intervenes with the logical optimization
Evaluation of RA operator trees
Algorithms of RA operators (see previous lecture)
