MySQL index is a data structure used to optimize the performance of database queries at the expense of additional writes and storage space to keep the index data structure up to date. It is used to quickly locate data without having to search every row in a table. Indexes can be created using one or more columns of a table, and each index is given a name. Indexes are especially useful for queries that filter results based on columns with a high number of distinct values.
Indexes are useful for our queries, but duplicate, redundant, and unused indexes reduce performance by confusing the optimizer with query plans, requiring the storage engine to maintain, calculate, and update more index statistics, as well as requiring more disk space.
Since MySQL 8.0, indexes can be marked as invisible. In this blog, I will detail how to detect duplicate and underused indexes as well as the new feature of invisible indexes and how it can help …[Read more]