Why did this postgres database upgrade fail?

Question

I am trying to upgrade from Postgresql 9.6 to 10 unsuccessfully.

I ran brew upgrade postgresql with success, then ran brew postgresql-upgrade-database with failure message. The issue seems to be this line:

lc_collate values for database "postgres" do not match: old "en_GB.UTF-8", new "en_US.UTF-8"

The whole message was:

    ==> Upgrading postgresql data from 9.6 to 10...
Stopping `postgresql`... (might take a while)
==> Successfully stopped `postgresql` (label: homebrew.mxcl.postgresql)
==> Moving postgresql data from /usr/local/var/postgres to /usr/local/var/postgres.o
The files belonging to this database system will be owned by user "jbkimac".
This user must also own the server process.

The database cluster will be initialized with locale "en_US.UTF-8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory /usr/local/var/postgres ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success. You can now start the database server using:

    /usr/local/opt/postgresql/bin/pg_ctl -D /usr/local/var/postgres -l logfile start

Performing Consistency Checks
-----------------------------
Checking cluster versions                                   ok
Checking database user is the install user                  ok
Checking database connection settings                       ok
Checking for prepared transactions                          ok
Checking for reg* data types in user tables                 ok
Checking for contrib/isn with bigint-passing mismatch       ok
Checking for invalid "unknown" user columns                 ok
Creating dump of global objects                             ok
Creating dump of database schemas
                                                            ok

lc_collate values for database "postgres" do not match:  old "en_GB.UTF-8", new "en_US.UTF-8"
Failure, exiting
Error: Upgrading postgresql data from 9.6 to 10 failed!
==> Removing empty postgresql initdb database...
==> Moving postgresql data back from /usr/local/var/postgres.old to /usr/local/var/p
==> Successfully started `postgresql` (label: homebrew.mxcl.postgresql)
Error: Failure while executing; `/usr/local/opt/postgresql/bin/pg_upgrade -r -b /usr/local/Cellar/postgresql/9.6.1/bin -B /usr/local/opt/postgresql/bin -d /usr/local/var/postgres.old -D /usr/local/var/postgres -j 8` exited with 1.

Can anyone help advise me as to how to fix this "en_GB.UTF-8", new "en_US.UTF-8" conflict issue?

Answer 1

brew services stop postgresql
brew postgresql-upgrade-database
brew services start postgresql

Answer 2

I had the same issue with brew postgresql-upgrade-database and had to change /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/cmd/brew-postgresql-upgrade-database.rb as @Thermatix mentioned. Both --lc-collate and --lc-ctype have to correspond with the current database settings. In my case ch_DE.UTF8 for both.