问题
I use Apartment gem in Rails 4 to support multi-tenancy in Postgres 9.3.3 on Heroku.
An error is occurred when Apartment gem creates a new tenant.
Deep investigation showed that a schema was created, but no tables inside.
Heroku logs showed an error:
PG::Error: ERROR: function pg_stat_statements_reset() does not exist
回答1:
When a new schema is created Postgres is trying to reset stats by executing the function pg_stat_statements_reset()
By default, this function can only be executed by superusers (from original doc).
Heroku doesn't give you superuser privileges. So you need to disable extension pg_stat_statements.
Solution 1 - Quick hot fix directly in DB
Execute SQL statement in schema public
DROP EXTENSION pg_stat_statements;
Solution 2 - via migration
1) Check the file db/schema.rb. Most probably it contains a line
enable_extension "pg_stat_statements"
2) Create a migration file
rails g migration DropExtensionPgStatStatements
3) define self.up method
def self.up
disable_extension "pg_stat_statements"
end
4) apply the migration
rake db:migrate
5) Now the file db/schema.rb should not contain that line
6) Commit changes (schema and migration files) and deploy to Heroku
rake deploy:production:migrations
Regarding the rake task see deploy.rake
来源：https://stackoverflow.com/questions/28452481/heroku-apartment-pgerror-error-function-pg-stat-statements-reset-does-no