A Errno::ENOMEM问题

Question

突然，在我的暂存服务器和prod服务器上(不同但使用相同的VPS提供程序)，我在使用我的ruby rails应用程序时收到了以下错误：

An Errno::ENOMEM occurred in projects#update:

Cannot allocate memory - identify -format %wx%h '/tmp/Lanscape_originalV220140520-32388-1alg9vz.png[0]'
vendor/bundle/ruby/1.9.1/gems/cocaine-0.3.0/lib/cocaine/command_line/runners/process_runner.rb:17:in `spawn’"

我怎么才能解决这个问题？

我临时解决了这个问题，重新启动了服务器

下面是导致此问题的项目更新文件：

class ProjectUpdatesController < ApplicationController
  before_filter :get_project
  def index
    @project_updates = @project.project_updates
    @project_update = ProjectUpdate.new
  end

  def show
    @project_update = ProjectUpdate.find(params[:id])
  end

  def new
    @project_update = ProjectUpdate.new
  end

  def edit
    @project_update = ProjectUpdate.find(params[:id])
  end

  def create
    @project_update = ProjectUpdate.new(params[:project_update])
    @project_update.project = @project
    return redirect_to :back, :alert => 'abc.' unless current_user.owner?(@project_update.project)
      if @project_update.save
        redirect_to project_project_updates_path(@project), :notice => 'abc.'
      else
        redirect_to project_project_updates_path(@project), :alert => 'abc.'
      end
  end

  def update
    @project_update = ProjectUpdate.find(params[:id])
    return redirect_to :back, :notice => 'you cannot edit project update.' unless current_user.owner?(@project_update.project)
      if @project_update.update_attributes(params[:project_update] )
        redirect_to project_project_updates_path(@project), :notice => 'abc.'
      else
        redirect_to project_project_updates_path(@project), :alert => 'abcy.'
      end
  end

  def destroy
    @project_update = ProjectUpdate.find(params[:id])
    return redirect_to :back, :alert => 'abc.' unless current_user.owner?(@project_update.project)
    @project_update.destroy

    respond_to do |format|
      format.html { redirect_to project_project_updates_url(@project) }
      format.json { head :no_content }
    end
  end

  def get_project
    @project = Project.find(params[:project_id])
  end

  def feed
    @project = Project.find(params[:project_id])
    @project_updates = @project.project_updates
    respond_to do |format|
      format.rss { render :layout => false }
    end
  end
end

Answer 1

显然，projects#update以某种方式触发了对identify -format ...的系统调用。gem 可卡因用于此。它在自述文件中写道：

https://github.com/thoughtbot/cocaine#posix-spawn

您可以通过安装posix派生gem来提高性能。在分叉命令行进程时，这个gem可以防止复制应用程序的堆。对于具有大堆的应用程序，增益可能很大。

我对此进行了测试并复制了错误。

#!/usr/bin/env ruby

require 'posix/spawn'

@arrays = []

def do_echos
        begin
                IO.popen('echo I am a child started with popen') { |io| puts io.read }
        rescue  Errno::ENOMEM => e
                puts "IO.popen: #{e.message}"
        end

        begin
                pid = Process.spawn('echo I am a child started with Process.spawn')
                Process.wait(pid)
        rescue Errno::ENOMEM => e
                puts "Process.spawn: #{e.message}"
        end

        child = POSIX::Spawn::Child.new('echo', 'I am a child started with posix_spawn');
        puts child.out
end

def fill_mem
        begin
                while true
                        @arrays << Array.new(10000000)
                end
        rescue NoMemoryError
                puts "Allocated arrays until out of memory..."
        end
end

do_echos
fill_mem
do_echos

这一产出如下：

我是个从波芬开始的孩子 我是一个从Process.spawn开始的孩子 我是一个从posix_spawn开始的孩子 分配数组直到内存耗尽..。 IO.popen:无法分配内存回显 Process.spawn:无法分配内存回显 我是一个从posix_spawn开始的孩子

最后，我建议你听从可卡因的建议。

要包含posix-派生，只需将其添加到您的Gemfile中，或者，如果您不使用bundler，则安装gem。

https://github.com/rtomayko/posix-spawn