simple_redis_profile.rb

#!/usr/bin/env ruby 
 
# Evaluates a sample of keys/values from each redis database, computing statistics for each key pattern: 
#   keys: number of keys matching the given pattern 
#   size: approximation of the associated memory occupied (based on size/length of value) 
#   percent: the proportion of this 'size' relative to the sample's total 
# 
# Copyright Weplay, Inc. 2010. Available for use under the MIT license. 
 
 
require 'rubygems' 
require 'redis' 
require 'yaml' 
 
SAMPLE_SIZE = 20_000  # number of keys to sample from each db before computing stats 
 
 
# Naive approximation of memory footprint: size/length of value. 
def redis_size(db, k) 
  t = db.type(k) 
  case t 
    when 'string' then db.get(k).length 
    when 'list'   then db.lrange(k, 0, -1).size 
    when 'zset'   then db.zrange(k, 0, -1).size 
    when 'set'    then db.smembers(k).size 
    when 'hash'   then db.hgetall(k).size 
    else raise("Redis type '#{t}' not yet supported.")  # TODO accommodate more types 
  end 
end 
 
def array_sum(array) 
  array.inject(0){ |sum, e| sum + e } 
end 
 
def redis_db_profile(db_name, sample_size = SAMPLE_SIZE) 
  db = Redis.new(:db => db_name) 
  keys = [] 
  sample_size.times { |i| keys << db.randomkey } 
  key_patterns = keys.group_by{ |key| key.gsub(/([\d\w]{20}|\d+)/, '#') } 
  data = key_patterns.map{ |pattern, keys| 
    [pattern, {'keys' => keys.size, 'size' => array_sum(keys.map{ |k| redis_size(db, k) })}] 
  }.sort_by{ |a| a.last['size'] }.reverse 
  size_sum = data.inject(0){|sum, d| sum += d.last['size'] } 
  data.each { |d| d.last['percent'] = '%.2f%' % (d.last['size'].to_f*100/size_sum) } 
end

db_names = `redis-cli info | grep ^db[0-9]`.split.map{ |line| line.scan(/^db\d+/).first } 
db_names.each do |name| 
  puts "\nProfiling \"#{name}\"...\n#{'-'*20}" 
  puts YAML.dump(redis_db_profile(name)) 
end 
 
puts "\nOverall statistics:\n#{'-'*20}" 
puts `redis-cli info | grep memory`