I support a PostgreSQL database it grew from 100 to 300 GB in couple months, I we need tuning all OS parameters (is a virtual enviroment). Currently the configuration is the follow:
Virtual Machine Ubuntu 18.04 12 CPUS 8 GB in RAM 400 in Disk Clúster database size 320 GB
Some queries have times too differents, the same query sometimes it execute in 8 10 seconds sometimes in 12 15 minutes, many querys make joins between 40, 50 millions rows. I know some factors like relation between entities affect times, but in general I suspect the mainly problem si resources in OS.
I suspect is a lack to memory ram but we need justify the change in OS RAM, so, How to calculate how too much memory ram need a PostgreSQL Server? Too need know how because the database size continue grows.
