Re: shared-buffers set to 24GB but the RAM only use 4-5 GB average

Response from you all are very precious.

@Merlin,
I'm misunderstood the question.
Yes, I didn't measure it. I only monitor RAM and CPU using htop (I also use
nmon for disk IO, iftop for the network utilization).
Did 1 connection need 1 core dedicatedly?
(I was having 40-80 connections in stable condition. And when the problem
happened the connections would be more than 150)

@Scott,
Just before the problem happened and when the problem happened, my server
didn't running out of IO/RAM/CPU.
The SSD IO total usage was 25-50% (I use nmon to monitor the disk IO)
The RAM total usage was 4-5GB of total 128GB (I monitor it using htop)
The CPU was 100% in 2 cores, 70% in 3 cores, the other 19 cores were under
5% (I monitor it using htop)
The network interface utilization was only 300-400 Mbps of total 1Gbps (I
monitor it using iftop)
So, maybe the 128GB RAM will never all be fully use by PostgreSQL?

I will test PostgreSQL with pg_bouncer in an identical logical (OS,
softwares, etc) condition and physical resource condition.

Respect,
FattahRozzaq