diff --git a/roles/moodle/tasks/main.yml b/roles/moodle/tasks/main.yml
index 40c68c519..14656b622 100644
--- a/roles/moodle/tasks/main.yml
+++ b/roles/moodle/tasks/main.yml
@@ -40,6 +40,11 @@
 #     enabled: no
 #   when: not moodle_enabled and not (pathagar_enabled is defined and pathagar_enabled)
 
+- name: "Set 'postgresql_install: True' if moodle_enabled"
+  set_fact:
+    postgresql_install: True
+  when: moodle_enabled | bool
+
 - name: "Set 'postgresql_enabled: True' if moodle_enabled"
   set_fact:
     postgresql_enabled: True
diff --git a/vars/default_vars.yml b/vars/default_vars.yml
index 256a6b6c5..258c2d5f6 100644
--- a/vars/default_vars.yml
+++ b/vars/default_vars.yml
@@ -239,13 +239,17 @@ pi_swap_file_size: 1024
 admin_console_install: True
 admin_console_enabled: True
 
-# MySQL MANDATORY - THESE 2 VARS HAVE NO EFFECT - SEE roles/0-init/tasks/main.yml & roles/mysql/tasks/main.yml
+# 2020-09-24: MySQL / MariaDB is MANDATORY but still evolving - please see:
+# https://github.com/iiab/iiab/blob/master/roles/mysql/tasks/install.yml
+# https://github.com/iiab/iiab/blob/master/roles/3-base-server/tasks/main.yml
+# THESE 2 LEGACY VARS ARE PRESERVED BUT HAVE NO EFFECT:
 mysql_install: True
 mysql_enabled: True
 
-# 2019-01-13: IIAB's use of NGINX is still evolving -- please review this
-# evolving doc: https://github.com/iiab/iiab/blob/master/roles/nginx/README.md
-# 2020-09-24: NGINX is mandatory, SEE: roles/3-base-server/tasks/main.yml
+# 2020-09-24: NGINX is MANDATORY but still evolving - please see:
+# https://github.com/iiab/iiab/blob/master/roles/nginx/README.md
+# https://github.com/iiab/iiab/blob/master/roles/3-base-server/tasks/main.yml
+# THESE 2 LEGACY VARS ARE PRESERVED BUT HAVE NO EFFECT:
 nginx_install: True
 nginx_enabled: True
 nginx_port: 80