You can add multiple indexes to any column in the materialized view to better support the queries you plan to run.
It is more efficient to create all the indexes needed before you insert any data into your database. You can drop any of the optional indexes later if you decide you do not need them.
Indexes can greatly improve the performance of searches on the indexed columns. However, indexes take up space within the database and slow down insert, update, and delete operations. This section helps you determine when you should create an index and how to achieve maximum performance from your index.
There are many situations in which creating an index improves the performance of a database. An index provides an ordering of a table's rows based on the values in some or all of the columns. An index allows the database server to find rows quickly. It permits greater concurrency by limiting the number of database pages accessed. An index also affords the database server a convenient means of enforcing a uniqueness constraint on the rows in a table.