Vincent Van Driessche <vincent(at)dabble(dot)be> writes:
> ... By running it before and after changing the `C` collation into `en_US.UTF-8`:
> UPDATE pg_database SET datcollate='en_US.UTF-8', datctype='en_US.UTF-8'
That is not, and I do not think ever will be, a supported operation.
If it breaks your database it's your own fault.
regards, tom lane