Covering Indexes


Covering Indexes

How does teradata optimizer pick indexes that cover a query, when there are more than one type of index created on a certain table.Suppose a user creates a single-table join index and Hash Index on the same table and both of them cover a certain query , which index does optimizer pick to cover the query.Does teradata support creation of different types of Indexes with same fields of a table?
Senior Apprentice

Re: Covering Indexes

Hi Leo,
as far as i know in older releases the optimizer just stopped after the first matching index was found, but now it should be based on cost estimates.
Teradata allows different index types on the same column, but of course you could have tested that easily :-)