Setup PostgreSQL 9.4 with custom locales on Debian

gistfile1.md

Add locale, e.g. pl_PL.UTF-8, you don't have to set it as system default:

dpkg-reconfigure locales

Install PostgreSQL

apt-get update
apt-get install posgresql-9.4

Installation adds a cluster with default locale, recreate it with the correct one. The operation will destroy existing data in the cluster.

pg_dropcluster --stop 9.4 main
pg_createcluster --locale pl_PL.UTF-8 --start 9.4 main

The resulting output may report incorrect locale, it will be system locale. However cluster will be set up correctly, to verify it run following queries:

su - postgres -c psql
    show LC_COLLATE;
    show LC_CTYPE;
    \q

Now you can load locale sensitive data.