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

Solution (By Examveda Team)

This question is about how MySQL's query optimizer chooses the best way to execute a query. The optimizer considers different execution plans, which are like recipes for how to fetch data. To make the process faster, the optimizer sometimes skips certain plans if it thinks they are unlikely to be efficient.

The system variable that controls this skipping is the optimizer_prune_level. This variable tells the optimizer how aggressively it should prune (skip) plans based on estimates of the number of rows that will be accessed.

Here's why the other options are incorrect:
* optimizer_search_depth: This variable limits the number of execution plans the optimizer explores, not how many plans it skips.
* optimizer_search: This option controls how the optimizer searches for plans, not whether it skips plans.
* optimizer_prune: There's no system variable called optimizer_prune.

So, the correct answer is Option A: optimizer_prune_level.