On Tue, Mar 28, 2023 at 6:06 PM Ron <ronljohnsonjr@xxxxxxxxx> wrote:
You can only get from parent to grandchild via child.id to grandchild.parent, so why not cluster grandchild on grandchild.parent?
Hi. I don't understand your question. Yes, of course, if I want all grand-children of a given parent, I'll do for example:
from grandchild gc
join child c on gc.parent = c.id
join parent p on c.parent = p.id
where p.name = $1
But w/o clustering on a denormalized grandchild.grandparent FK column, as Peter showed,
and cluster only on grandchild.parent, that's not going to access a mostly continuous range
of pages to fetch those all grandchild rows for that one parent. But probably 10 to 50 "row-clusters",
given the fan-out I mentioned earlier at the child-table level. Or am I missing something?
