[CentOS] OT - pushing database updates to web browser

Wed Feb 7 13:53:11 UTC 2018
Gary Stainburn <gary at ringways.co.uk>

This is O/T apart from the fact that the server is Centos running Apache / 
Postgresql.

I want to develop a real time (ish) dashboard type web page showring extracts 
of the contents of a table.  I would like any changes that occur to be pushed 
to the web clients rather than have the clients poll the database.

Based on the fact that I have not managed to come up with a successful Google 
search phrase I think this may not be possible, but just in case I thought 
I'd ask here.

If it's not possible, can anyone suggest the most efficient / responsive 
polling techniques?