Invisible and descending indexes

The invisible index is a special feature which will mark an index as unavailable for the optimizer. MySQL 8 will maintain invisible indexes and keep them up-to-date when data is modified. This will apply on indexes other than primary key. As we know, indexes are visible by default; we have to make them invisible explicitly at the time of creation, or by using the alter command. MySQL 8 provides the VISIBLE and INVISIBLE keywords to maintain index visibility. A descending index is the method of storing key values in descending order. A descending index is more efficient, as it can be scanned in the forward order. Let's see these indexes in detail, with examples.

Invisible index

As mention previously, an invisible index is not used by the optimizer. Then what is the use of this index? This question comes into our mind, right? We will explain to you some of the use cases for invisible indexes:

• When many indexes are defined, but you are not sure which index is not...