CHAPTER 12

image

Execution Plan Optimization and Consistency

When you issue a SQL statement, the query optimizer creates an execution plan that describes the combination of steps Oracle takes to retrieve or modify the data. For example when you submit a query, the optimizer quickly produces several execution plans and will determine which plan is most efficient. In most scenarios, the prior behavior results in adequate-performing execution plan. However, you will encounter situations where query performance is poor and you need to understand the optimizer’s choice of an execution plan. Listed next are features you can use to guide the decision path ...

Get Oracle Database 12c Performance Tuning Recipes: A Problem-Solution Approach now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.