ruby mysql vs sqlite

ruby_gil_test.rb

#!/usr/bin/env ruby
#
require 'benchmark'
require 'thread'
require 'rubygems'
require 'sqlite3'
require 'mysql2'

SQLITE3_DB = 'test.db'

def new_sqlite_connection
  SQLite3::Database.new SQLITE3_DB
end

def sqlite_query
  new_sqlite_connection.execute 'select * from dummies'
end

# seed sqlite
File.delete SQLITE3_DB if File.exists? SQLITE3_DB
new_sqlite_connection.tap do |db|
  db.execute "create table dummies ( a integer );"
  db.execute "insert into dummies values ( 1000 );"
  (1..20).each do |i| # 2 ^ 20
    db.execute "insert into dummies (a) select d.a from dummies as d;"
  end
end

def mysql_query
  db = Mysql2::Client.new
  db.query("SELECT SLEEP(3)")
end

def sleep_some_time
  50.times { sleep 0.1 }
end

Benchmark.bm do |b|
  b.report('sleep         ') { sleep_some_time }
  b.report('mysql         ') { mysql_query }
  b.report('mysql + sleep ') do
    threads = []
    threads << Thread.new { sleep_some_time }
    threads << Thread.new { mysql_query }
    threads.each &:join
  end
  b.report('sqlite        ') { sqlite_query }
  b.report('sqlite + sleep') do
    threads = []
    threads << Thread.new { sleep_some_time }
    threads << Thread.new { sqlite_query }
    threads.each &:join
  end
end

# ruby -v
# 1.9.3-p194 
#
# gem list sqlite
# *** LOCAL GEMS ***
# sqlite3 (1.3.6)
# sqlite3-ruby (1.3.3)
#
# sqlite3 --version
# 3.7.7 2011-06-25 16:35:41 8f8b373eed7052e6e93c1805fc1effcf1db09366
#
# gem list mysql2
# *** LOCAL GEMS ***
# mysql (2.8.1)
# mysql2 (0.3.11)
#
# mysql --version
# mysql  Ver 14.14 Distrib 5.5.25a, for osx10.7 (i386) using readline 5.1
#
# ./ruby_gil_test.rb
#        user     system      total        real
# sleep           0.000000   0.000000   0.000000 (  5.047439)
# mysql           0.010000   0.000000   0.010000 (  3.008452)
# mysql + sleep   0.000000   0.000000   0.000000 (  5.049623)
# sqlite          1.360000   0.020000   1.380000 (  1.384636)
# sqlite + sleep  1.340000   0.030000   1.370000 (  5.912172)