require "active_record"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Migration.class_eval do
  create_table(:records) do |t|
    t.string :column
  end
end

data = 50_000.times.map { |i| Hash[column: "Column #{i}"] }

# =============================================================

columns = data.first.keys
values_list = data.map do |hash|
  hash.values.map do |value|
    ActiveRecord::Base.connection.quote(value)
  end
end

ActiveRecord::Base.connection.execute <<-SQL
INSERT INTO records (#{columns.join(",")}) VALUES
#{values_list.map { |values| "(#{values.join(",")})" }.join(", ")}
SQL

# Takes 2 seconds, because it does a single multi INSERT statement.
# But the code is even uglier than with Arel.