A concern that adds a perfomatic .bulk_update method for ActiveRecord classes.

bulk_updatable.rb

module BulkUpdatable
  extend ActiveSupport::Concern

  self.included do |base|
    # Usage:
    #
    # User.bulk_update([{id: 1, name: 'Foo'}, {id: 2, name: 'Bar'}])
    # (1.5ms)  UPDATE "users" SET "id" = 1, "name" = 'Foo' WHERE "users"."id" = 1; 
    #          UPDATE "users" SET "id" = 2, "name" = 'Bar' WHERE "users"."id" = 2
    # => #<PG::Result:0x007f814aa04c40 status=PGRES_COMMAND_OK ntuples=0 nfields=0 cmd_tuples=1> 
    #
    def self.bulk_update(attributes_list)
      table    = Arel::Table.new(self.table_name)
      sql_sets = []

      attributes_list.each do |attributes|
        update_manager = Arel::UpdateManager.new table.engine
        sets = attributes.map { |k, v| [table[k], v] }
        update_manager.set(sets).where(table[:id].eq(attributes[:id])).table(table)
        sql_sets << update_manager.to_sql
      end

      ActiveRecord::Base.connection.execute(sql_sets.join(";\n"))
    end
  end
end

Benchmark of 1000 entries updates:

                           user     system      total        real
Simple interator       1.760000   0.620000   2.380000 (  2.985689)
Using transaction      1.200000   0.310000   1.510000 (  1.702462)
Upsert gem             0.150000   0.050000   0.200000 (  0.686520)
BulkUpdatable          0.060000   0.000000   0.060000 (  0.209489)

Alternatives:

• https://rubygems.org/gems/bulk_update
• https://github.com/fiksu/bulk_data_methods