Query rewrites - PowerPoint PPT Presentation

Lecture 14: Query Optimization

Lecture 14: Query Optimization. This Lecture. Query rewriting Cost estimation We have learned how atomic operations are implemented and their cost We’ll complete the picture by estimating the cost query plans Including computing the size of the output (reduction factors)

★ ★ ★ ★ ★

560 views • 53 slides

Query Optimization

Query Optimization. Query Optimization Process (simplified a bit). Parse the SQL query into a logical tree: identify distinct blocks (corresponding to nested sub-queries or views). Query rewrite phase: apply algebraic transformations to yield a cheaper plan.

★ ★ ★ ★ ★

753 views • 52 slides

Query Optimization

sname. rating &gt; 5. bid=100 . (Simple Nested Loops). sid=sid. Sailors. Reserves. Query Optimization. Goal:. Declarative SQL query. Imperative query execution plan:. SELECT S.sname FROM Reserves R, Sailors S WHERE R.sid=S.sid AND R.bid=100 AND S.rating&gt;5.

★ ★ ★ ★ ★

197 views • 17 slides

View Query rewrites PowerPoint (PPT) presentations online in SlideServe. SlideServe has a very huge collection of Query rewrites PowerPoint presentations. You can view or download Query rewrites presentations for your school assignment or business presentation. Browse for the presentations on every topic that you want.