What are indexed views and how does it improve performance?
Indexed view is a virtual table which represents an output of a select statement. In general when we create a view the view does not store any data. So when we query a view it queries the underlying base table. But when we create indexed views, result set is persisted on the hard disk which can save lot of overheads. So let’s understand advantages and disadvantages of indexed views. Advantages By creating indexed views you can store pre-computed values , expensive computations and join in the indexed views so that we do not need to recalculate them again and again. Disadvantages Indexed views are not suitable for tables which are highly transactional because SQL engine needs to also update indexed views if base table changes.
