> A question on 20s postgresql time - It does not look like you are accounting for reading data from disk

I choose the data size so that it would fit in memory on the machine I was testing on. fwiw, there's still a ton of overhead Postgres has that the toy example does not. For example Postgres will serialize the numbers into tuples and need to deserialize them to execute the query. That's why it's not an apples-to-apples comparison