ruby thread使用总结

ruby thread 使用总结

ruby thread 基本用法

puts "start"
Thread.new{
  sleep 1
  puts "In Thread"
  }
puts "end"

>start
>end

进程结束子线程也随之结束

puts "start"
Thread.new{
  sleep 1
  puts "In Thread"
  }.join
puts "end"

>start
>In Thread
>end

使用 Thread 实例方法 join，进程会等待子线程执行完成后继续向下执行

启用多个子线程

一般方式： ruby threads = [] 5.times do threads << Thread.new{ sleep 1 puts "thread_id #{Thread.current.object_id}" } end threads.each{|thread| thread.join} puts "end"

错误的方式： ruby 5.times do Thread.new{ sleep 1 puts "thread_id #{Thread.current.object_id}" }.join end puts "end" 这样会在一个线程结束后再启动下一个线程

线程状态

Thread.current.status

"sleep" Returned if this thread is sleeping or waiting on I/O

"run" When this thread is executing

"aborting" If this thread is aborting

false When this thread is terminated normally

nil If terminated with an exception.

传入参数

Thread.new(:args_1 => 1,:args_2){ |args|
    p args
}.join

>{:args_1 => 1,:args_2 => 2}

多线程使用ActiveRecord连接池进行查询

ActiveRecord 版本4.1.1 adaptor： mysql2 pool： 10

class Keyword < ActiveRecord::Base
end
index = 0
11.times do 
    Thread.new{
        keywords = Keyword.where(:status => 10).to_a
        puts index
        p keywords
    }.join
    index += 1
end

启动第11个线程时会报错：获取mysql连接超时 原因是前面10个线程与mysql的连接并未自动释放，mysql连接池达到最大连接数

class Keyword < ActiveRecord::Base
end
index = 0
11.times do 
    Thread.new{
        keywords = Keyword.where(:status => 10).to_a
        puts index
        p keywords
        ActiveRecord::Base.connection_pool.release_connection
    }.join
    index += 1
end

调用方法ActiveRecord::Base.connectionpool.releaseconnection释放连接池内连接，程序正常运行