SQL Quiz: Five Popular Myths About SQL Performance
As a database administrator, I get a lot of requests for help with poorly performing SQL queries. Here are some popular myths about SQL performance. How many do you believe?
- The execution plans in the test and production databases are identical.
- Explain Plan and Autotrace display the execution plan used to execute the query.
- The execution plan does not change.
- The cost-based optimizer selects the optimal execution plan—the one with the lowest cost.
- A SQL query has an optimal execution plan—one with the lowest cost.