Question

Which system variable tells the optimizer to skip certain plans based on estimates of the number of rows accessed for each table?

(a) optimizer_prune_level

(b) optimizer_search_depth

(c) optimizer_search

(d) optimizer_prune

This question was posed to me in an online interview.

I'd like to ask this question from MySQL Query Optimizer topic in chapter Query Optimization of MySQL

Answer 1

Correct answer is (a) optimizer_prune_level

The explanation is: The optimizer_prune_level variable tells the optimizer to skip certain plans based on estimates of the number of rows accessed for each table. This option is kept on by default.