JRuby on Rails and
Thread Safety
Naoto Takai
Akasaka.rb / Itochu Techno-Solutions Corp.
29 November 2008

‣ JRuby on Rails and Thread Safety
‣ ActiveRecord and Connection Pooling
‣ JNDI and Connection Pooling

‣ JRuby on Rails and Thread Safety
‣ ActiveRecord and Connection Pooling
‣ JNDI and Connection Pooling

Ruby on Rails 2.2 Release Notes

Ruby on Rails 2.1 or Prior
Ruby
Process Rails
Instance
Ruby
Process Rails Database
Instance
Ruby
Process Rails
Instance

JRuby on Rails 2.1 or Prior
Thread
JRuby
Rails
Instance
Thread
JRuby
Rails Database
Instance
Thread
JRuby
Rails
Instance
Thread

One JRuby Instance,
One Database Connection
JRuby
Thread Rails Database
Instance

JRuby on Rails 2.2 or Later
Thread
JRuby
Rails
Instance
Thread
JRuby Connection
Rails Database
Instance Pool
Thread
JRuby
Rails
Instance
Thread

One JRuby Instance,
Many Database Connections
Thread
JRuby
Rails Database
Instance
Thread
You need less JRuby instances
per database connections.

‣ JRuby on Rails and Thread Safety
‣ ActiveRecord and Connection Pooling
‣ JNDI and Connection Pooling

ActiveRecord Connection Pool
ActiveRecord::Base.establish_connection(
:adapter => \"mysql\",
:username => \"root\",
:database => \"database\",
:pool => 5
)

Demo Code
10.times do
Thread.new do
ActiveRecord::Base.connection_pool \\
.with_connection do |c|
ret = c.execute(\"select connection_id()\")
puts \"Connection ID: %s\" % ret.fetch_row
end
end
end

ActiveRecord Connection Pooling (1)
Check-out Connect
Connection
ActiveRecord Database
Pool
Connection

ActiveRecord Connection Pooling (2)
Check-out
Connection
ActiveRecord Database
Pool
Connection

ActiveRecord Connection Pooling (3)
Wait
Check-out
Connection
ActiveRecord Database
Pool
Connection
Check-out
Check-in
ActiveRecord

‣ JRuby on Rails and Thread Safety
‣ ActiveRecord and Connection Pooling
‣ JNDI and Connection Pooling

‣ JNDI
(Java Naming and Directory Service)
‣ Binding a name to an object.
‣ Look-up the object by name.

Using JNDI Look-up
ActiveRecord::Base.establish_connection(
:adapter => \"jdbc\",
:jndi => \"jdbc/MySQL\",
:driver => \"com.mysql.jdbc.Driver\",
:pool => 5
)

JNDI Look-up
Look-up
Reference
Connection
Client Database
Pool
Data
Source

Java EE Application Server
Connection Pooling
Connect or
Check-out Reconnect
ActiveRecord App Server
ActiveRecord Connection Connection
Pool Pool
Connection Connection
Check-in Disconnect
Database