Is hiding an index the same as deleting an index?

Hiding an index is fundamentally different from deleting an index. When an index is hidden, it is still present in the database but is not used by the query planner to execute queries. This means that while the hidden index can be retained for potential future use or for testing purposes, it does not contribute to the performance of query operations until it is made visible again.

On the other hand, deleting an index completely removes it from the database, including all its associated resources. Once deleted, it cannot be reverted or reinstated without creating a new index. This permanence is a critical distinction: hiding maintains the structure of the index and its metadata, allowing for flexibility in managing query performance without the need to recreate the index later.

Therefore, the statement that hiding does not remove the index captures the essence of how hiding and deleting differ. Hiding allows for temporary exclusion from query planning, while deletion is a final, irreversible action.