Getting poor performance from a query that contains OR or IN? Disjunction queries, where the filter includes OR or IN, can have poor performance due to the way they use (or do not use) indexes. This tutorial demonstrates some techniques for tuning them.
Background – Many SQL queries include multiple predicates combined with an “OR” operator, aka the “disjunction” operator. Did you know that B-Tree indexes are of limited value with these predicates? Composite indexes and bitmaps might help, but, all too often, the optimizer (CBO) will produce a Full Table Scan.
Course Features
- Lecture 1
- Quiz 0
- Duration 14 minutes
- Skill level All levels
- Language English
- Students 0
- Assessments Yes
