Backup all db records older than x

db.rake

namespace :db do
  desc "Backup DB as separate schema"
  task :backup_to_schema, [:created_at] => :environment do |t, args|
    schema = 'copy'
    created_at = args.created_at || 2.years.ago
    ApplicationRecord.connection.execute(
      "DROP SCHEMA #{schema} CASCADE; 
      CREATE SCHEMA copy"
    )
    ActiveRecord::Base.connection.execute "SET search_path TO public, #{schema}"
    File.read(File.expand_path '~/tables.txt').each_line do |table_name|
      table_name.sub! /\n/, ''
      unless ApplicationRecord.connection.table_exists? table_name
        raise "#{table_name} doesn't exist in DB"
      end
      ApplicationRecord.connection.execute(
        "create table #{schema}.#{table_name} (like #{table_name} including all)")
      puts "Created #{table_name}"
      if ApplicationRecord.connection.column_exists? table_name, 'created_at'
        ApplicationRecord.connection.execute(
          "INSERT INTO #{schema}.#{table_name} SELECT * FROM #{table_name} 
          WHERE created_at < '#{created_at.to_formatted_s :db}'")
      else 
        ApplicationRecord.connection.execute(
          "INSERT INTO #{schema}.#{table_name} SELECT * FROM #{table_name}")
      end
      puts "Copied #{table_name}"
    end
  end
end