diff --git a/postgresql/defaults/main.yml b/postgresql/defaults/main.yml
index 1c4e7238..543f1707 100644
--- a/postgresql/defaults/main.yml
+++ b/postgresql/defaults/main.yml
@@ -3,10 +3,10 @@
 postgresql_databases: []
 
 # Tuning
-postgresql_shared_buffers: 4GB
+postgresql_shared_buffers: "{{ (ansible_memtotal_mb * 0.25) | int }}MB"
 postgresql_work_mem: 8MB
 postgresql_random_page_cost: 1.5
-postgresql_effective_cache_size: 14GB
+postgresql_effective_cache_size: "{{ (ansible_memtotal_mb * 0.5) | int }}MB"
 
 # PostgreSQL version
 postgresql_version: '9.4'
diff --git a/postgresql/tasks/config.yml b/postgresql/tasks/config.yml
index 0ed0a324..6a606165 100644
--- a/postgresql/tasks/config.yml
+++ b/postgresql/tasks/config.yml
@@ -21,3 +21,5 @@
     group: postgres
     mode: "0644"
   notify: restart postgresql
+
+- meta: flush_handlers