Do you have any source for this? I'd love to know more about how they re rank items incrementally.

Do they actually update every single row in the database every 5 minutes? It seems too slow.

Source: dang is one of the employees of Y Combinator who help run HN.

Dang--might be good to have some way to indicate that so new folks understand your special role in the community here

HN doesn't use a database. There are no rows. Just one process on one server with everything in memory. Data is lazy loaded from flat files on-demand.

I assumed that in memory they had something structurally resembling a relational database but they might not. It would never even occur to me to not use a database for something like this.

Thank you. I did not expect that!