client = TinyTds::Client.new username: ENV["SQL_SERVER_USERNAME"],
                             password: ENV["SQL_SERVER_PASSWORD"],
                             port: ENV["SQL_SERVER_PORT"],
                             host: ENV["SQL_SERVER_HOST"],
                             database: ENV["SQL_SERVER_DB"]
query = "SELECT TOP(60000) [Institution of Higher Education Key]
     ,[Date Key]
     ,[Academic Term Key]
     ,[IPEDS Demographics Key]
     ,[IPEDS Fall Enrollment Attribute Key]
     ,[IPEDS Enrollment Headcount]
     ,[Calculated Full Time Equivalent Enrollment-Fall Headcount Basis]
 FROM [dw].[IPEDS Fall Enrollment Fact]
GO"
result = client.execute("EXECUTE AS USER='ADND\\rsnodgra' #{query}")
report = MemoryProfiler.report do
  CSV.open('dataset_exports/tinytds_memory_test.csv', 'w') do |csv|
      csv << result.fields
      result.each(:as => :array, :cache_rows => false) do |row|
        csv << row
      end
    end
end
report.pretty_print

# 74.449254 MB of memory
allocated memory by gem
-----------------------------------
  41808214  ruby-2.1.8/lib
  19200000  activesupport-4.1.15
  13441040  other

allocated memory by file
-----------------------------------
  41808214  /usr/local/rvm/rubies/ruby-2.1.8/lib/ruby/2.1.0/csv.rb
  16800000  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/activesupport-4.1.15/lib/active_support/core_ext/numeric/conversions.rb
  13441040  (irb)
   2400000  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/activesupport-4.1.15/lib/active_support/core_ext/big_decimal/conversions.rb


#####################
#####################
#####################
#####################

@db = Sequel.tinytds user: ENV["SQL_SERVER_USERNAME"],
                   password: ENV["SQL_SERVER_PASSWORD"],
                   port: ENV["SQL_SERVER_PORT"],
                   host: ENV["SQL_SERVER_HOST"],
                   database: ENV["SQL_SERVER_DB"],
                   timeout: 20
query = "SELECT TOP(60000) [Institution of Higher Education Key]
     ,[Date Key]
     ,[Academic Term Key]
     ,[IPEDS Demographics Key]
     ,[IPEDS Fall Enrollment Attribute Key]
     ,[IPEDS Enrollment Headcount]
     ,[Calculated Full Time Equivalent Enrollment-Fall Headcount Basis]
 FROM [dw].[IPEDS Fall Enrollment Fact]
GO"

report = MemoryProfiler.report do
  CSV.open('dataset_exports/sequel_memory_test.csv', 'w') do |csv|
    csv << @db["EXECUTE AS USER='ADND\\rsnodgra'; #{query}"].first.keys
    @db["EXECUTE AS USER='ADND\\rsnodgra'; #{query}"].each do |row|
      csv << row.values
    end
  end
end
report.pretty_print

# 105.182268 MB
Total allocated: 105182268 bytes (1440296 objects)
Total retained:  1411 bytes (12 objects)

allocated memory by gem
-----------------------------------
  41808494  ruby-2.1.8/lib
  38411103  sequel-4.35.0
  19200000  activesupport-4.1.15
   5761534  other
      1137  tiny_tds-1.0.4

allocated memory by file
-----------------------------------
  41808494  /usr/local/rvm/rubies/ruby-2.1.8/lib/ruby/2.1.0/csv.rb
  38405678  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/sequel-4.35.0/lib/sequel/adapters/tinytds.rb
  16800000  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/activesupport-4.1.15/lib/active_support/core_ext/numeric/conversions.rb
   5761534  (irb)
   2400000  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/activesupport-4.1.15/lib/active_support/core_ext/big_decimal/conversions.rb
      2441  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/sequel-4.35.0/lib/sequel/dataset/actions.rb
      1352  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/sequel-4.35.0/lib/sequel/dataset/query.rb
      1137  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/tiny_tds-1.0.4/lib/tiny_tds/client.rb
      1008  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/sequel-4.35.0/lib/sequel/database/connecting.rb
       464  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/sequel-4.35.0/lib/sequel/connection_pool/threaded.rb
       160  /usr/local/rvm/gems/ruby-2.1.8@Fenrir/gems/sequel-4.35.0/lib/sequel/database/dataset.rb