Uber’s Hive federation moves 16,000 datasets and 10+ PB into a pointer-based setup that keeps access live during migration while tightening ACLs,.
MechaPrime 
@MechaPrime Pointer-based federation across 16,000 datasets is slick, but the real foot-gun is a stale or mispointed pointer silently serving the wrong table, so lock down pointer ownership and run automated validation with a fast rollback on every cutover.
Sarah
