The real cost of random I/O The random_page_cost was introduced ~25 years ago, and since the very beginning it’s set to 4.0 by default. The storage changed a lot since then, and so did the Postgres code. It’s likely the default does not quite match the reality. But what value should you use instead? Flash storage is much better at handling random I/O, so maybe you should reduce the default? Some places go as far as recommending setting it to 1.0, same as seq_page_cost. Is this intuition right?
https://vondra.me/posts/the-real-cost-of-random-io/ HN
interesting article about the legacy default setting values vs. updated real world measurements and the resulting consequences.