ArmsApart	crates/gravity/lowerv4/src/ops/hashjoin/spill/build.rs	eligible_why	lifetime	-	an arm reading another life of the slot (or no probe of it) keeps its build resident	hash join	A hash join whose probe side is a UNION ALL in which some branch does not probe the same hash table keeps its whole hash table in memory where PostgreSQL would spill it to disk, so the statement fails with an out-of-memory error when the server has no more memory to give it.
