|GIN "posting tree" leaf page. Compressed TIDs are in orange.|
It wasn't very time consuming to add these enhancements, because most index access methods share the same basic approach to page layout. I plan to add support for the two remaining index access methods (BRIN and SP-GiST) early in the new year. My hope is that this will spur interest in the internals of PostgreSQL index access methods (PDF link), and how they deal with index tuples and space management (PDF link).
Hat tip to Pat Shaughnessy, who just today wrote a great blog post on the internals of GiST. The fact that he has done such a thorough job of explaining how GiST works to a wider audience is encouraging.