ERROR: must be owner of language plpgsql

For new readers, I read this older post after having run into this error in one of my own projects. I strongly feel that giving the app's PostgreSQL a superuser role is a terrible idea and changing the template is not ideal either. Since the referenced PSQL commands that are added by db:structure:dump are not needed by the Rails app's database, I have written a custom rake task that comments out the problematic lines in structure.sql. I have shared that code publicly on Github as a Gist at https://gist.github.com/rietta/7898366.

I had the same problem. I fixed my template with the commands below

psql template1
template1=# alter role my_user_name with superuser;

read more at http://gilesbowkett.blogspot.com/2011/07/error-must-be-owner-of-language-plpgsql.html

The solution was as follows:

On my installation, there are standard templates template0 and template1 - at least as I understand it postgres will look for the highest numbered templateN when creating a new database, unless the template is specified.

In this instance, as template0 included plpgsql, so did template1… the idea being that you will customise template1 to suite your site specific default needs, and in the case that you blow everything up, you would restore template1 from template0.

As my site specific requirement was to install plpgsql as part of the automated build of my web application (a step we had to keep to maintain 8.4 compatibility) - the solution was easy: remove plpgsql from template1 and the warning/error went away.

In the case that the site-specific defaults would change, and we should need to go back to the default behaviour, we would simply remove template1 and recreate it (which would use template0)