Databases are fast for querying large amounts of data, but terrible at fetching small amounts of data quickly.Databases perform terribly on benchmarks for getting single rows from small tables.  In Oracle, fetching a 100x2 matrix of integers takes 500us, while fetching 1000x2 matrix takes 1000us.  I get similar (worse) performance in MySQL and Postgres.This is hundreds of times slower than a key value store.  It's crazy that databases are so slow in 2020.  It massively influences how we build applications, and I don't understand why they have to be so bad at being key-value stores.As far as I understand, modern databases are quite complex bits of software. For example, Oracle performs a lot of IPC between listener, writer and log processes.  Postgres has a single process per connection that has to be synchronised with other processes.What are some of the techniques that people on Hacker News have used to mitigate this problem?