Unlocking high-performance PostgreSQL with key memory optimizations

I generally use this: https://pgtune.leopard.in.ua/

Does not instill confidence when the queries they provide don't work.

For anyone curious, the corrected query:

SELECT sum(blks_hit)::numeric / nullif(sum(blks_hit + blks_read), 0) AS cache_hit_ratio FROM pg_stat_database;