It's livenotes from a presentation, I expect Reinout van Rees noted the parts that interested him as the actual presentation has what you think "right":
> If you have lots of memory, set it between 2GB and 4GB. Anything above 8GB exceeds what it is designed to handle
From the slides:
> Above 32GB (lucky you!), set to 8GB.
> This is a great way to cause your database machine to swap to death.
from the slides:
> But be careful: It can use that amount of memory per planner node.
maintenance_work_mem: 2GB is plenty. [...] 10% is way too high.
from the slides:
> 10% of system memory, up to 1GB. Maybe even higher if you are having VACUUM problems.
Hi, I'm the Reinout that made the notes. Yes, it was a live summary and his slides went by very fast. I'm surprised how much I got written down. So I had to leave stuff out, for instance the >32GB comment (which I did as it seemed applicable only to few people).
Masklinn, thanks for doing this bit of checking! For many people (including myself :-) the summary will be enough, but checking the actual presentation is a good idea if you run into problems.
> It's also pretty dangerous and wrong.
It's livenotes from a presentation, I expect Reinout van Rees noted the parts that interested him as the actual presentation has what you think "right":
> If you have lots of memory, set it between 2GB and 4GB. Anything above 8GB exceeds what it is designed to handle
From the slides:
> Above 32GB (lucky you!), set to 8GB.
> This is a great way to cause your database machine to swap to death.
from the slides:
> But be careful: It can use that amount of memory per planner node.
maintenance_work_mem: 2GB is plenty. [...] 10% is way too high.
from the slides:
> 10% of system memory, up to 1GB. Maybe even higher if you are having VACUUM problems.
(emphasis mine)