[substack]

The VPS we're running on has 60GB of RAM which should be plenty but the ingest program needs more work to use less memory so it stops crashing when denormalizing multipolygon relations, which involves denormalizing ways which fetch nodes... all referenced by ID which has not much locality spread across the pbf file. And if you write to temporary storage it can use a lot of disk and denormalization based on the on-disk format can get really slow. It's just all very tricky to get working well within reasonable time constraints (less than a week of processing ideally) and a reasonable memory footprint.