Comparing runtime characteristics of individual transactions, one transaction, and one statement.

bulk_insert.rb

 def insert_many
   1000.times { SeoRank.create! }
 end

 start = Time.now
 ActiveRecord::Base.transaction { insert_many }
 puts "N transactions: #{ Time.now - start }"

 start = Time.now
 ActiveRecord::Base.transaction { insert_many }
 puts "One transaction: #{ Time.now - start }"

 values = (["('a')"] * 1000).join(',')
 start = Time.now
 ActiveRecord::Base.connection.execute "insert into seo_ranks (href) values #{ values }"
 puts "Hand rolled SQL: #{ Time.now - start }"

$ be rails runner "$( cat transaction.rb )"
N transactions: 1.390017
One transaction: 1.110242
Hand rolled SQL: 0.011879