cruby_bench.rb

```ruby
require 'benchmark'
require 'mysql2'

Benchmark.bm do |x|
  x.report do
    100.times do
      client = Mysql2::Client.new(host: 'localhost', username: 'isucon', password: 'isucon', database: 'isuconp')
      client.query('SELECT * FROM comments LIMIT 10').each do |item|
        item['id']
        item['post_id']
      end
      client.close
    end

  end
end
```


```ruby
require 'jdbc/mysql'
require 'benchmark'

Jdbc::MySQL.load_driver

Benchmark.bm do |x|
  x.report do
    100.times do

      Java::com.mysql.jdbc.Driver
      uri = 'jdbc:mysql://localhost/isuconp'
      connection = java.sql.DriverManager.get_connection(uri, "isucon", "isucon")
      statement = connection.create_statement
      result = statement.execute_query('SELECT * FROM comments LIMIT 10')

      while result.next
        result.getObject('id')
        result.getObject('post_id')
      end

      statement.close
      connection.close
    end

  end
end
```


```
$ ruby -v
ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-linux]
$ ruby ruby_bench.rb
       user     system      total        real
   0.020000   0.010000   0.030000 (  0.054094)
```

```
$ jruby -v
jruby 9.1.5.0 (2.3.1) 2016-09-07 036ce39 Java HotSpot(TM) 64-Bit Server VM 24.80-b11 on 1.7.0_80-b15 +jit [linux-x86_64]
$ jruby jruby_bench.rb
       user     system      total        real
  1.170000   0.010000   1.180000 (  0.767505)
```

```
$ jruby -Xcompile.invokedynamic=true -v
jruby 9.1.5.0 (2.3.1) 2016-09-07 036ce39 Java HotSpot(TM) 64-Bit Server VM 24.80-b11 on 1.7.0_80-b15 +indy +jit [linux-x86_64]
$ jruby -Xcompile.invokedynamic=true jruby_bench.rb
       user     system      total        real
  1.250000   0.040000   1.290000 (  0.900037)
```

jruby is slower. with invokedynamic, it rather became more slower.