The last day we've encountered an issue what i think is somewhat severe if you want to do either OS upgrades with CentOS or even binary upgrades with an existing PostgreSQL instance to a new machine with locale de_DE.UTF-8 and thus i'd like to share here. Here are the details: Originally a Postgres 9.4 was running on CentOS 5.11/x86_64. The database in question was initialized with locale de_DE.UTF-8 and previously upgraded via pg_upgrade from 9.2 and then running without any issues for a while. After that the customer migrated to new hardware with an OS upgrade to CentOS 6.6/x86_64. This was done by just remounting the SAN LUN on the new machine. So far so good, no issues. However, after a while developers realized duplicate values in unique keys with certain types of string values (the format is described in the examples below). So the suspicion was that this has to do with locales. And yes, the german locale collation order changed: CentOS 5.11 has: echo -e '156\n1-5-6\n110\n1-1-0' | LANG=de_DE.UTF-8 sort 110 1-1-0 156 1-5-6 CentOS 6.6 does: echo -e '159\n1-5-9\n110\n1-1-0' | LANG=de_DE.UTF-8 sort 1-1-0 110 1-5-9 159 Interestingly CentOS 7.1 restores the behavior from CentOS 5.11 echo -e '159\n1-5-9\n110\n1-1-0' | LANG=de_DE.UTF-8 sort 110 1-1-0 159 1-5-9 There are entries in the CentOS bugtracker regarding other locales: https://bugs.centos.org/view.php?id=7009 https://bugs.centos.org/view.php?id=6210 So users are encouraged to carefully test their platforms when upgrading. Checks show that at least RHEL6 and RHEL7 have the same issue, too. -- Thanks Bernd -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
