INVISIBLE INDEX

INVISIBLE INDEX is a SQL statement in the Indexes category. Makes an index invisible to the optimizer without dropping it. Useful for testing performance without dropping. The syntax is ALTER TABLE table_name ALTER INDEX index_name INVISIBLE;. It returns invisible index. A typical example: ALTER TABLE employees ALTER INDEX idx_last_name INVISIBLE; -- Index is still maintained but NOT used by queries -- Re-enable: ALTER TABLE employees ALTER INDEX idx_last_name VISIBLE; -- Useful for testing query performance without/with index A close relative is CREATE INDEX, which creates an index on one or more columns to speed up query performance. A close relative is DROP INDEX, which removes an existing index from a table. A close relative is COMPOSITE INDEX, which an index on multiple columns. Column order matters — queries use leftmost prefix. More about this category: Database indexes — CREATE INDEX, UNIQUE INDEX, COMPOSITE INDEX, DROP INDEX.