Postgres vs Redis Object Storage Benchmarks

benchmark.rb

require "pg"
require "redis"

words = File.read("/usr/share/dict/words").split "\n"
pgconn = PGconn.open :dbname => "test_hstore", :port => 5433, :user => "test_user", :password => "changeme"
redis = Redis.new
reps = [1,10,100,1000,10000]
pg_inserts = []
pg_selects = []
redis_sets = []
redis_gets = []

reps.each do |num|
  t0 = Time.now
  num.times do |idx|
    pgconn.exec "INSERT INTO test_table VALUES (#{idx+1}, hstore('#{words[idx]}'=>'#{idx}'))"
  end
  pg_inserts << Time.now - t0

  t0 = Time.now
  num.times do
    pgconn.exec "SELECT * FROM test_table"
  end
  pg_selects << Time.now - t0

  pgconn.exec "TRUNCATE TABLE test_table"
end

reps.each do |num|
  t0 = Time.now
  num.times do |idx|
    redis.hset idx, words[idx], idx
  end
  redis_sets << Time.now - t0

  t0 = Time.now
  num.times do |idx|
    redis.hget idx, words[idx]
  end
  redis_gets << Time.now - t0

  num.times do |idx|
    redis.del idx
  end
end

log = File.open "benchmarks.log", "w"

log.puts "Postgres Benchmarks: "
log.puts "  Inserts:"
reps.each_with_index do |num, idx|
  log.puts "    #{num}:  #{pg_inserts[idx]}"
end
log.puts "  Selects:"
reps.each_with_index do |num, idx|
  log.puts "    #{num}:  #{pg_selects[idx]}"
end
log.puts " "
log.puts "Redis Benchmarks: "
log.puts "  Sets:"
reps.each_with_index do |num, idx|
  log.puts "    #{num}:  #{redis_sets[idx]}"
end
log.puts "  Gets:"
reps.each_with_index do |num, idx|
  log.puts "    #{num}:  #{redis_gets[idx]}"
end

benchmarks.log

Postgres Benchmarks: 
  Inserts:
    1:  0.00212
    10:  0.008992
    100:  0.045435
    1000:  0.443837
    10000:  4.660529
  Selects:
    1:  0.033782
    10:  0.003462
    100:  0.023476
    1000:  1.077131
    10000:  164.168994
 
Redis Benchmarks: 
  Sets:
    1:  0.001448
    10:  0.001114
    100:  0.744665
    1000:  0.296913
    10000:  1.122622
  Gets:
    1:  0.000119
    10:  0.001038
    100:  0.020944
    1000:  0.098915
    10000:  0.92371

The Postgres GET test is invalid as you have a bug in your code.

You are selecting the whole table X times, compared to redis where you are selecting each individual value.

pgconn.exec "SELECT * FROM test_table"

redis.hget idx, words[idx]