diff --git a/README.md b/README.md
index e2e9d62..df4779a 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,7 @@ The following key commands are available in the console UI:
 * `B` - sort by bandwidth
 * `T` - toggle sorting by ascending / descending order
 * `Q` - quits
+* `D` - quits and dumps keys to dump.csv file
 
 ## Status bar
 
diff --git a/bin/mctop b/bin/mctop
index 20da5f8..ca8acda 100755
--- a/bin/mctop
+++ b/bin/mctop
@@ -10,6 +10,7 @@ require 'rubygems'
 require 'cmdline'
 require 'sniffer'
 require 'ui'
+require 'csv'
 
 @config = CmdLine.parse(ARGV)
 
@@ -21,6 +22,7 @@ ui      = UI.new(@config)
 sort_mode  = :reqsec
 sort_order = :desc
 done       = false
+dump       = false
 
 # trap most of the typical signals
 %w[ INT QUIT HUP KILL ].each do |sig|
@@ -44,6 +46,9 @@ until done do
   case key
     when /[Qq]/
       done = true
+    when /[Dd]/
+      done = true
+      dump = true
     when /[Cc]/
       sort_mode = :calls
     when /[Ss]/
@@ -70,3 +75,11 @@ sniffer.done
 if sniff_thread.join(0)
   sniff_thread.kill
 end
+
+if dump
+  CSV.open(@config[:dump], "w") do |csv|
+    sniffer.metrics[:calls].each do |k,v|
+      csv << [k,v,sniffer.metrics[:objsize][k]]
+    end
+  end
+end
diff --git a/lib/cmdline.rb b/lib/cmdline.rb
index 5197d2b..939c91f 100644
--- a/lib/cmdline.rb
+++ b/lib/cmdline.rb
@@ -5,6 +5,8 @@ class CmdLine
   def self.parse(args)
     @config = {}
 
+    @config[:dump] = "dump.csv"
+
     opts = OptionParser.new do |opt|
       opt.on('-i', '--interface=NIC', 'Network interface to sniff (required)') do |nic|
         @config[:nic] = nic
diff --git a/lib/ui.rb b/lib/ui.rb
index 3ca7420..d3ba2c4 100644
--- a/lib/ui.rb
+++ b/lib/ui.rb
@@ -30,7 +30,8 @@ def initialize(config)
       'S' => "sort by size",
       'R' => "sort by req/sec",
       'B' => "sort by bandwidth",
-      'T' => "toggle sort order (asc|desc)"
+      'T' => "toggle sort order (asc|desc)",
+      'D' => "dump"
     }
   end
 
diff --git a/script/group_by_key.rb b/script/group_by_key.rb
new file mode 100755
index 0000000..76d9697
--- /dev/null
+++ b/script/group_by_key.rb
@@ -0,0 +1,224 @@
+#!/usr/bin/ruby
+
+require 'csv'
+require 'curses'
+
+include Curses
+include Curses::Key
+
+def input_handler
+  # Curses.getch has a bug in 1.8.x causing non-blocking
+  # calls to block reimplemented using IO.select
+  if RUBY_VERSION =~ /^1.8/
+   refresh_secs = 500.to_f / 1000
+
+    if IO.select([STDIN], nil, nil, refresh_secs)
+      c = getch
+      c.chr
+    else
+      nil
+    end
+  else
+    getch
+  end
+end
+
+init_screen
+cbreak
+curs_set(0)
+Curses.timeout = 500
+
+if can_change_color?
+  start_color
+  init_pair(0, COLOR_WHITE, COLOR_BLACK)
+  init_pair(1, COLOR_WHITE, COLOR_BLUE)
+  init_pair(2, COLOR_WHITE, COLOR_RED)
+  init_pair(3, COLOR_WHITE|A_BOLD, COLOR_CYAN)
+end
+
+commands = {
+  'Q' => "quit",
+  'J' => "join",
+  "S" => "split",
+  "P" => "prev",
+  "N" => "next",
+  "D" => "dump"
+}
+
+# load stats
+dump = "dump.csv"
+metrics = {}
+metrics[:raw] = {}
+metrics[:raw][:calls] = {}
+metrics[:raw][:keys] = {}
+metrics[:raw][:bw] = {}
+CSV.open(dump, 'r') do |row|
+  metrics[:raw][:calls][row[0].to_s] = row[1].to_i
+  metrics[:raw][:keys][row[0].to_s] = 1
+  metrics[:raw][:bw][row[0].to_s] = (row[1].to_i) * (row[2].to_i)
+end
+keys = metrics[:raw][:calls].keys.sort
+prefix = []
+update = true
+
+done = false
+dump = false
+offset = 0
+posy = 0
+
+until done do
+
+  # compute aggregate
+  if update
+    top = []
+    metrics[:agg] = {}
+    metrics[:agg][:calls] = {}
+    metrics[:agg][:keys] = {}
+    metrics[:agg][:bw] = {}
+    keys.each do |k|
+      t = :raw
+      prefix.each do |p|
+        if k[0,p.length] == p
+          t = :agg
+          if metrics[t][:calls].has_key?(p)
+            metrics[t][:calls][p] += metrics[:raw][:calls][k]
+            metrics[t][:keys][p] += 1
+            metrics[t][:bw][p] += metrics[:raw][:bw][k]
+          else
+            top << [p,t]
+            metrics[t][:calls][p] = metrics[:raw][:calls][k]
+            metrics[t][:keys][p] = 1
+            metrics[t][:bw][p] = metrics[:raw][:bw][k]
+          end
+          break
+        end
+      end
+      if t == :raw
+        top << [k,t]
+      end
+    end
+    update = false
+  end
+
+  # render header
+  stat_cols = %w[ calls objsize keys size(kb) ]
+  stat_col_width = 10
+  stat_cols = stat_cols.map { |c| sprintf("%#{stat_col_width}s", c) }
+  key_col_width = cols - (stat_cols.length * stat_col_width)
+  attrset(color_pair(1))
+  setpos(0,0)
+  addstr(sprintf "%-#{key_col_width}s%s", "memcache key", stat_cols.join)
+
+  # render stats
+  maxlines = lines - 2
+  for i in 0..maxlines-1
+    if i == posy
+      attrset(color_pair(3))
+    else
+      attrset(color_pair(0))
+    end
+    if i < offset + top.length
+      k,t = top[i + offset]
+      if k.length > key_col_width
+        display_key = k[0..key_col_width-4]
+        display_key = "#{display_key}..."
+      else
+        display_key = k
+      end
+      calls = metrics[t][:calls][k]
+      dkeys = metrics[t][:keys][k]
+      size = metrics[t][:bw][k].to_f / 1024
+      if calls > 0
+        objsize = 1024 * size / calls
+      else
+        objsize = 0
+      end
+      line = sprintf "%-#{key_col_width}s %9.d %9.2f %9.d %9.2f",
+        display_key, calls, objsize, dkeys, size
+    else
+      line = " " * cols
+    end
+    setpos(1+i, 0)
+    addstr(line)
+  end
+
+  # render footer
+  footer_text = commands.map { |k,v| "#{k}:#{v}" }.join(' | ')
+  setpos(lines-1, 0)
+  attrset(color_pair(2))
+  addstr(sprintf "%-#{cols}s", footer_text)
+
+  refresh
+
+  case input_handler
+    when /[Qq]/
+      done = true
+    when /[Pp]/
+      if posy > 0
+        posy -= 1
+      else
+        if offset > 0
+          offset -= 1
+        end
+      end
+    when /[Nn]/
+      if posy < maxlines-1 and posy + offset < top.length-1
+        posy += 1
+      else
+        if offset < top.length-maxlines
+          offset +=1
+        end
+      end
+    when /[Jj]/
+      if offset + posy < top.length-2
+        p = ""
+        k = top[offset + posy][0]
+        n = top[offset + posy + 1][0]
+        for i in 0..k.length-1
+          if i < n.length-1
+            if k[i] == n[i]
+              p << k[i]
+            else
+              break
+            end
+          else
+            break
+          end
+        end
+        if p.length > 0
+          prefix << p
+          prefix = prefix.sort
+          update = true
+        end
+      end
+    when /[Ss]/
+      if top[offset + posy][1] == :agg
+        prefix.delete(top[offset + posy][0])
+        prefix = prefix.sort
+        update = true
+      end
+    when /[Dd]/
+      done = true
+      dump = true
+  end
+end
+
+nocbreak
+close_screen
+
+if dump
+  puts "Dumping stats.."
+  CSV.open("stat.csv", "w") do |csv|
+    top.each do |k,t|
+      calls = metrics[t][:calls][k]
+      dkeys = metrics[t][:keys][k]
+      size = metrics[t][:bw][k].to_f / 1024
+      if calls > 0
+        objsize = 1024 * size / calls
+      else
+        objsize = 0
+      end
+      csv << [k, calls, objsize, dkeys, size]
+    end
+  end
+end