Apply recommended tweaks on Postgres images

Apply few recommended optimalizations on Postgres 9.3/9.4
redstack images.

Implements: blueprint postgres-configuration-groups
Change-Id: Ib7dad31dafdf97adb3200493b334ff93be93fc7b

scripts/files/elements/fedora-postgresql/install.d/10-postgresql

@@ -3,6 +3,31 @@
 set -e
 set -o xtrace
 
+cat > "/etc/sysctl.d/10-postgresql-performance.conf" << _EOF_
+# See 'http://www.postgresql.org/docs/9.3/static/kernel-resources.html'
+# for best practices.
+# It is recommended to disable memory overcommit,
+# but the Python interpreter may require it on smaller flavors.
+# We therefore stick with the heuristic overcommit setting.
+vm.overcommit_memory=0
+
+_EOF_
+
+cat > "/etc/rc.local" << _EOF_
+# See 'http://www.postgresql.org/docs/9.3/static/kernel-resources.html'
+# Disable Linux kernel transparent huge pages. This feature is not supported by
+# by Postgres 9.3 and may negatively impact performance of the database.
+if test -f /sys/kernel/mm/redhat_transparent_hugepage/defrag; then
+  echo never > /sys/kernel/mm/redhat_transparent_hugepage/defrag
+fi
+if test -f /sys/kernel/mm/redhat_transparent_hugepage/enabled; then
+  echo never > /sys/kernel/mm/redhat_transparent_hugepage/enabled
+fi
+
+exit \$?
+
+_EOF_
+
 dnf install -y http://yum.postgresql.org/9.3/fedora/fedora-21-x86_64/pgdg-fedora93-9.3-2.noarch.rpm
 dnf install -y postgresql93-server postgresql93-contrib
 

scripts/files/elements/ubuntu-postgresql/install.d/10-postgresql

@@ -4,6 +4,32 @@ set -e
 set -o xtrace
 
 export DEBIAN_FRONTEND=noninteractive
+
+cat > "/etc/sysctl.d/10-postgresql-performance.conf" << _EOF_
+# See 'http://www.postgresql.org/docs/9.3/static/kernel-resources.html'
+# for best practices.
+# It is recommended to disable memory overcommit,
+# but the Python interpreter may require it on smaller flavors.
+# We therefore stick with the heuristic overcommit setting.
+vm.overcommit_memory=0
+
+_EOF_
+
+cat > "/etc/rc.local" << _EOF_
+# See 'http://www.postgresql.org/docs/9.3/static/kernel-resources.html'
+# Disable Linux kernel transparent huge pages. This feature is not supported by
+# by Postgres 9.3 and may negatively impact performance of the database.
+if test -f /sys/kernel/mm/transparent_hugepage/defrag; then
+  echo never > /sys/kernel/mm/transparent_hugepage/defrag
+fi
+if test -f /sys/kernel/mm/transparent_hugepage/enabled; then
+  echo never > /sys/kernel/mm/transparent_hugepage/enabled
+fi
+
+exit \$?
+
+_EOF_
+
 apt-get -y install postgresql-9.3
 
 # Install the native Python client.