The best way to improve efficiency is to avoid work. In this presentation we look at several production examples of ways in which excess work can be eliminated. The options vary from basic configuration to simple code changes, from rephrasing the requirement to restating the logic and being aware that you may have missed features that are perfect matches for your requirement.
We consider array fetching, precision updates, side effects of analytic functions, best use of PL/SQL, pros and cons of temporary tables and intermediate results, and the dangers of using scalar subqueries that might make queries easier to understand but could make them much slower to run. Along the way we tick off a couple of technical details about indexes, analytic functions, and the 12c match_recognize functionality.
Speaker: Jonathan Lewis
Title: “Just Don’t Do It.”
Presented on: Monday, June 15th 2020, 14:10 CET