Inspired by this answer, we created the following database.rake
file. Where the original answer worked only for PostgreSQL 9.1, this one is modified to work for PostgreSQL 9.2 as well. The mechanism is not the prettiest: when the 9.1 command fails, it simply executes the 9.2 command. But the most important thing: it works!
#{Rails.root}/lib/tasks/databases.rake
# monkey patch ActiveRecord to avoid There are n other session(s) using the database.
def drop_database(config)
case config['adapter']
when /mysql/
ActiveRecord::Base.establish_connection(config)
ActiveRecord::Base.connection.drop_database config['database']
when /sqlite/
require 'pathname'
path = Pathname.new(config['database'])
file = path.absolute? ? path.to_s : File.join(Rails.root, path)
FileUtils.rm(file)
when /postgresql/
begin
ActiveRecord::Base.establish_connection(config.merge('database' => 'postgres', 'schema_search_path' => 'public'))
ActiveRecord::Base.connection.select_all("select * from pg_stat_activity order by procpid;").each do |x|
if config['database'] == x['datname'] && x['current_query'] =~ /<IDLE>/
ActiveRecord::Base.connection.execute("select pg_terminate_backend(#{x['procpid']})")
end
end
ActiveRecord::Base.connection.drop_database config['database']
rescue # in PG 9.2 column procpid was renamed pid and the query status is checked not using 'current_query' but using 'state'
ActiveRecord::Base.establish_connection(config.merge('database' => 'postgres', 'schema_search_path' => 'public'))
ActiveRecord::Base.connection.select_all("select * from pg_stat_activity order by pid;").each do |x|
if config['database'] == x['datname'] && x['state'] =~ /idle/
ActiveRecord::Base.connection.execute("select pg_terminate_backend(#{x['pid']})")
end
end
ActiveRecord::Base.connection.drop_database config['database']
end
end
end