I've been reading the FSM README file lately (src/backend/storage/freespace/README), and I'm puzzled by one of the graph (the binary tree structure of an FSM file). Here it is:
4 4 2 3 4 0 2 <- This level represents heap pages
Shouldn't the last line be: 4 3 2 0
(ie, highest number of free space on the left node, lowest on the right one)
Probably just nitpicking, but still, I'm wondering if I missed something out.
No, that's not how it works. Each number at the bottom level corresponds to a particular heap page. The first number would be heap page #0 (which has 3 units of free space), the second heap page #1 (with 4 units of free space) and so forth. Each node on the upper levels stores the maximum of its two children.
