In PostgreSQL, indexing is a large field and covers many aspects of database work. As I have outlined in this book already, indexing is key to performance. There is no good performance without proper indexing. Therefore, it is worth inspecting those indexing-related features in more detail.
Understanding additional B-tree features
Combined indexes
In my job as a professional PostgreSQL support vendor, I am often asked about the difference between a combined and individual indexes. In this section, I will try to shed some light on this question.
The general rule is this: if a single index can answer your question, it is usually the best choice. However, you cannot index all possible combinations of fields people are filtering on. What you can do is use the properties...
