Ruby script to get the postgres database tables sizes and store them into the hash.

postgres_table_size.rb

sql = "SELECT tablename FROM pg_tables WHERE schemaname = 'public' ORDER BY tablename;"
tables = ActiveRecord::Base.connection.execute(sql)
tables_size={}
tables.each do |table|
  name = table['tablename']
  sql = "SELECT pg_size_pretty(pg_total_relation_size('#{name}'));"
  res = ActiveRecord::Base.connection.execute(sql)
  puts "#{name} #{res[0]['pg_size_pretty']}"
  tables_size["#{name}"] = res[0]['pg_size_pretty']
  puts tables_size
end