Moving beyond standard B-trees, this chapter explores the physical structure and use cases of PostgreSQL's specialized index types. We will dissect GiST (Generalized Search Tree), GIN (Generalized Inverted Index), BRIN (Block Range Index), and SP-GiST. Students will learn how to write operator classes and how the engine determines index applicability.

Outside Reading

• Official Docs: Chapter 65: B-Tree Indexes, GiST Indexes, GIN Indexes, BRIN Indexes. (Assign the "Implementation" subsections of each).
• GitHub Source: src/backend/access/nbtree/nbtinsert.c. Have students read the _bt_insertonpg() function comments to understand how page splits work at the physical level.