In this blog, we continue our exploration on PostgreSQL indexes which we started here. In that article, we learned what an index is, and how exactly indexes can help with query execution. But there is much more to learn about indexes! In this blog, we will keep exploring B-tree indexes. We will learn whether (and how) database constraints and indexes are related (or not), how exactly index bitmap scan works, and explore some additional index options available in PostgreSQL.
Indexes and Constraints
In the previous article we learned that the most helpful indexes are indexes with the lowest selectivity,