我正在尝试将应用程序从 Rails 3.0.3 移植到 Rails 3.1rc ......我认为我没有错过任何东西，就配置而言。该过程在 Rails 3.0.X 中完美运行，而不是在 3.1rc 中。
在控制台中，我这样做：
Resque.enqueue(EncodeSong, Song.find(20).id, Song.find(20).unencoded_url)
到目前为止一切正常。Resque-web 报告没有失败的作业。而且，我从模块 EncodeSong 中得到了两个“放置”。
但是，再次运行Resque.enqueue(EncodeSong, Song.find(20).id, Song.find(20).unencoded_url)将在 resque-web 中返回以下错误（如下）。为了使错误消失，我必须关闭正在运行的进程：QUEUE=* rake environment resque:work并在控制台窗口中重新运行它。但是在第一次尝试 Resque.enqueue() 之后问题又回来了。
Class
EncodeSong
Arguments
20
"https://bucket_name.s3.amazonaws.com/unencoded/users/1/songs/test.mp3"
Exception
PGError
Error
server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request.
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:272:in `exec'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:272:in `block in clear_cache!'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:271:in `each_value'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:271:in `clear_cache!'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:299:in `disconnect!'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_pool.rb:191:in `block in disconnect!'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_pool.rb:190:in `each'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_pool.rb:190:in `disconnect!'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activesupport-3.1.0.rc1/lib/active_support/core_ext/module/synchronization.rb:35:in `block in disconnect_with_synchronization!'
/Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activesupport-3.1.0.rc1/lib/active_support/core_ext/module/synchronization.rb:34:in `disconnect_with_synchronization!'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_pool.rb:407:in `remove_connection'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_specification.rb:116:in `remove_connection'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_specification.rb:79:in `establish_connection'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_specification.rb:60:in `establish_connection'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_specification.rb:55:in `establish_connection'
/Users/Chris/Sites/site_name/lib/tasks/resque.rake:17:in `block (2 levels) in <top (required)>'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/resque-1.16.1/lib/resque/worker.rb:355:in `call'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/resque-1.16.1/lib/resque/worker.rb:355:in `run_hook'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/resque-1.16.1/lib/resque/worker.rb:162:in `perform'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/resque-1.16.1/lib/resque/worker.rb:130:in `block in work'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/resque-1.16.1/lib/resque/worker.rb:116:in `loop'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/resque-1.16.1/lib/resque/worker.rb:116:in `work'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/resque-1.16.1/lib/resque/tasks.rb:27:in `block (2 levels) in <top (required)>'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/task.rb:205:in `call'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/task.rb:205:in `block in execute'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/task.rb:200:in `each'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/task.rb:200:in `execute'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/task.rb:144:in `invoke'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/application.rb:112:in `invoke_task'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/application.rb:90:in `block (2 levels) in top_level'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/application.rb:90:in `each'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/application.rb:90:in `block in top_level'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/application.rb:84:in `top_level'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/application.rb:62:in `block in run'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/lib/rake/application.rb:59:in `run'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/gems/rake-0.9.0/bin/rake:31:in `<top (required)>'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/bin/rake:19:in `load'
/Users/Chris/.rvm/gems/ruby-1.9.2-p136@railspre/bin/rake:19:in `<main>'
这是我的其余相关代码：
/config/initializers/resque.rb
require 'resque'
uri = URI.parse(APP_CONFIG['redis_to_go_url'])
Resque.redis = Redis.new(:host => uri.host, :port => uri.port, :password => uri.password)
# Load all jobs at /app/jobs
Dir["#{Rails.root}/app/jobs/*.rb"].each { |file| require file }
/app/jobs/encode_song.rb
module EncodeSong
@queue = :encode_song
def self.perform(media_id, s3_file_url)
begin
media = Song.find(media_id)
puts 'foo11111'
puts media.id
rescue
puts "Error #{$!}"
end
end
end
lib/tasks/resque.rake
require 'resque/tasks'
task "resque:setup" => :environment do
ENV['QUEUE'] = '*'
# ONLY on Heroku, since they are still running PostgreSql 8 on their shared plan.
# This block of code is not needed on PostgreSql 9, as tested on local environment.
# Issue: My best guess is that master resque process establishes connection to db,
# while loading rails app classes, models, etc, and that connection becomes corrupted
# in fork()ed process (on exit?). Possible fix is to reestablish the connection the AR
# after a Resque fork.
Resque.after_fork do |job|
ActiveRecord::Base.establish_connection
end
end
desc "Alias for resque:work (To run workers on Heroku)"
task "jobs:work" => "resque:work"
不太确定，但可能与这个问题有些相关。我的猜测是，主 resque 进程建立与 db 的连接，同时加载 rails 应用程序类、模型等，并且该连接在 fork()ed 进程中损坏（退出时？）。
任何帮助/方向将不胜感激。
编辑：
如果我从lib/tasks/resque.rake中删除以下块：
Resque.after_fork do |job|
ActiveRecord::Base.establish_connection
end
在控制台中，运行Resque.enqueue(EncodeSong, Song.find(20).id, Song.find(20).unencoded_url)
我收到一个新错误（在运行 QUEUE=* rake environment resque:work 的控制台中）：
Error PGError: ERROR: prepared statement "a3" already exists
: SELECT "songs".* FROM "songs" WHERE "songs"."id" = $1 LIMIT 1
看来，这可能是适配器的错误？这里可能是错的。你的意见？