What is recommended postgresql connection count for NGL?

[Angel]

Hi,
I had a new NGL(3.1.2) server setup early this year on *inx system with postgresql 8.4.20
but lately NGL server had some issue in postgresql, postgres process consumed whole lot of memory
for a certain amount of time. When there's memory usage spikes,
database server need be restarted and NGL server went back to normal.
During those memory usage spikes, users even cannot access to the NGL web front.
I am not sure it also has effect on tomcat.

Symptoms:

NGL_Client



NGL_Desktop



NGL_Workbench



PGAdminIII




Temporary Solution:
Increase max_connection count from default "100" to "200"
Increase shared_buffer size from default "24" to "128" MB

Progress After Setting Update (10-May-2018)~(13-May-2018)



However I would like to request expertise advice on postgresql connection counts per user ratio so that I can properly do necessary adjustment.
Thanks.
Angel