benching script, work in progress

script/measure.rb

@@ -0,0 +1,126 @@
+# using this script to try figure out why Rails 2 is slower that 1.9
+#
+require 'objspace'
+require 'benchmark'
+require 'ruby-prof'
+
+require File.expand_path(File.dirname(__FILE__) + "/../config/environment")
+
+
+def profile_allocations(name)
+  GC.disable
+  initial_size = ObjectSpace.count_objects
+  yield
+  changes = ObjectSpace.count_objects
+  changes.each do |k,v|
+    changes[k] -= initial_size[k]
+  end
+  puts "#{name} changes"
+  changes.sort{|a,b| b[1] <=> a[1]}.each do |a,b|
+    next if b <= 0
+    # 1 extra hash for tracking
+    puts "#{a} #{a == :T_HASH ? b-1 : b}"
+  end
+  GC.enable
+end
+
+def profile(name, &block)
+  puts "Profiling all object allocation for #{name}"
+  GC.start
+  GC.disable
+
+  items = []
+  objs = []
+
+  ObjectSpace.trace_object_allocations do
+    block.call
+
+    ObjectSpace.each_object do |o|
+      objs << o
+    end
+
+    objs.each do |o|
+      g = ObjectSpace.allocation_generation(o)
+      if g
+        l = ObjectSpace.allocation_sourceline(o)
+        f = ObjectSpace.allocation_sourcefile(o)
+        c = ObjectSpace.allocation_class_path(o)
+        m = ObjectSpace.allocation_method_id(o)
+        items << "Allocated #{c} in #{m} #{f}:#{l}"
+      end
+    end
+  end
+
+  items.group_by{|x| x}.sort{|a,b| b[1].length <=> a[1].length}.each do |row, group|
+    puts "#{row} x #{group.length}"
+  end
+
+  GC.enable
+  profile_allocations(name, &block)
+end
+
+
+# User.limit(10).to_a
+# RubyProf.start
+# User.limit(10).to_a
+# result = RubyProf.stop
+# # printer = RubyProf::GraphPrinter.new(result)
+# printer = RubyProf::FlatPrinter.new(result)
+# printer.print(STDOUT, :min_percent => 2)
+# 
+# exit
+# 
+# # User.limit(10).to_a
+# User.limit(10).select(:created_at).to_a
+# 
+# profile("limit 10") do
+#   User.limit(10).select(:created_at).to_a
+# end
+# 
+# exit
+# User.limit(10).to_a
+# exit
+#
+User.select('id, 2 bob').first
+Benchmark.bmbm do |x|
+
+  x.report("find") do
+    100.times{User.find(1)}
+  end
+
+  x.report("grab 10 users created_at") do
+    100.times{User.limit(10).select(:created_at).to_a}
+  end
+
+  x.report("grab 10 users id") do
+    100.times{User.limit(10).select(:id).to_a}
+  end
+
+  x.report("grab 10 users") do
+    100.times{User.limit(10).to_a}
+  end
+
+
+  x.report("pg direct grab 10 users") do
+    100.times do
+      r = ActiveRecord::Base.connection.raw_connection.async_exec("select * from users limit 10")
+      r.fields.each_with_index do |f,i|
+        r.ftype(i)
+      end
+      r.each_row do |x|
+        x
+      end
+    end
+  end
+
+end
+
+
+# profile("find") do
+#   User.find(1)
+# end
+# puts
+# profile("where") do
+#   User.where(id: 1).first
+# end
+