我在mac上，通过postgress。app使用postgres。我解决了这个问题，只是退出，重新开始应用程序。

退出postgres并重新启动。很简单，但每次对我都有效，而其他cli命令有时不能。

我的工作如下:

sudo gitlab-ctl stop
sudo gitlab-ctl start gitaly
sudo gitlab-rake gitlab:setup [type yes and let it finish]
sudo gitlab-ctl start

我正在使用: gitlab_edition:“gitlab-ce” gitlab_version:“12.4.0-ce.0.el7”

答案隐藏在上面的一条评论中:brew服务重新启动postgresql

没有必要放弃。只需删除并重新创建公共模式。在大多数情况下，这有完全相同的效果。

namespace :db do

desc 'Clear the database'
task :clear_db => :environment do |t,args|
  ActiveRecord::Base.establish_connection
  ActiveRecord::Base.connection.tables.each do |table|
    next if table == 'schema_migrations'
    ActiveRecord::Base.connection.execute("TRUNCATE #{table}")
  end
end

desc 'Delete all tables (but not the database)'
task :drop_schema => :environment do |t,args|
  ActiveRecord::Base.establish_connection
  ActiveRecord::Base.connection.execute("DROP SCHEMA public CASCADE")
  ActiveRecord::Base.connection.execute("CREATE SCHEMA public")
  ActiveRecord::Base.connection.execute("GRANT ALL ON SCHEMA public TO postgres")
  ActiveRecord::Base.connection.execute("GRANT ALL ON SCHEMA public TO public")
  ActiveRecord::Base.connection.execute("COMMENT ON SCHEMA public IS 'standard public schema'")
end

desc 'Recreate the database and seed'
task :redo_db => :environment do |t,args|
  # Executes the dependencies, but only once
  Rake::Task["db:drop_schema"].invoke
  Rake::Task["db:migrate"].invoke
  Rake::Task["db:migrate:status"].invoke 
  Rake::Task["db:structure:dump"].invoke
  Rake::Task["db:seed"].invoke
end

end

我是这样解决的:

在我的Windows8 64位，只是重新启动服务:postgresql-x64-9.5