EM Postgresql Sequel

Installation

• gem install pg
• gem install eventmachine
• gem install sequel
• gem install em-postgresql-sequel

Examples

Run 3 fiber queries concurrently, utilizing 3 connections

['logger', 'pg', 'sequel', 'eventmachine', 'em-postgresql-sequel', 'fiber'].each do |lib| 
  require lib
end

EM::run do
  Fiber.new do
    DB = Sequel.connect 'postgres://user:pass@localhost:5432/db', :logger => Logger.new(STDOUT), :max_connections => 3, :pool_class => EM::Sequel::FiberedConnectionPool

    (1..10).each do |num|
      Fiber.new do
        res = DB["select 'f#{num}' as fiber, pg_sleep(3)"].all
        puts "f#{num} done, res: #{res.inspect}"
      end.resume
    end
  end.resume
end

Run 1 fiber query at a time, utilizing 1 connection

['logger', 'pg', 'sequel', 'eventmachine', 'em-postgresql-sequel', 'fiber'].each do |lib| 
  require lib
end

EM::run do
  Fiber.new do
    DB = Sequel.connect 'postgres://user:pass@localhost:5432/db', :logger => Logger.new(STDOUT), :max_connections => 1, :pool_class => EM::Sequel::FiberedConnectionPool

    (1..10).each do |num|
      Fiber.new do
        res = DB["select 'f#{num}' as fiber, pg_sleep(3)"].all
        puts "f#{num} done, res: #{res.inspect}"
      end.resume
    end
  end.resume
end

Known Issues

• disconnected connection

Todos

• add some test cases

Credits

• https://www.github.com/igrigorik/em-synchrony
• https://www.github.com/leftbee/em-postgresql-adapter