I'm creating a website using Laravel 5. I'm using queues with beanstalkd with 2 tubes. I have 10 workers monitored by daemontools. 5 workers process tube A and B. The other 5 workers only process tube B.
Things work great most of the time, but occasionally tube B seems to lock up. The logs show that the workers are throwing an exception.
[2015-04-24 07:09:36] local.ERROR: exception 'Pheanstalk\Exception\ServerException' with message 'Cannot delete job 273812: NOT_FOUND' in /x/website/vendor/pda/pheanstalk/src/Command/DeleteCommand.php:44
Stack trace:
#0 /x/website/vendor/pda/pheanstalk/src/Connection.php(121): Pheanstalk\Command\DeleteCommand->parseResponse('NOT_FOUND', NULL)
#1 /x/website/vendor/pda/pheanstalk/src/Pheanstalk.php(384): Pheanstalk\Connection->dispatchCommand(Object(Pheanstalk\Command\DeleteCommand))
#2 /x/website/vendor/pda/pheanstalk/src/Pheanstalk.php(67): Pheanstalk\Pheanstalk->_dispatch(Object(Pheanstalk\Command\DeleteCommand))
#3 /x/website/vendor/laravel/framework/src/Illuminate/Queue/Jobs/BeanstalkdJob.php(73): Pheanstalk\Pheanstalk->delete(Object(Pheanstalk\Job))
#4 /x/website/vendor/laravel/framework/src/Illuminate/Queue/CallQueuedHandler.php(46): Illuminate\Queue\Jobs\BeanstalkdJob->delete()
#5 /x/website/vendor/laravel/framework/src/Illuminate/Queue/Jobs/Job.php(126): Illuminate\Queue\CallQueuedHandler->call(Object(Illuminate\Queue\Jobs\BeanstalkdJob), Array)
#6 /x/website/vendor/laravel/framework/src/Illuminate/Queue/Jobs/BeanstalkdJob.php(51): Illuminate\Queue\Jobs\Job->resolveAndFire(Array)
#7 /x/website/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(207): Illuminate\Queue\Jobs\BeanstalkdJob->fire()
#8 /x/website/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(159): Illuminate\Queue\Worker->process('beanstalkd', Object(Illuminate\Queue\Jobs\BeanstalkdJob), '20', '120')
#9 /x/website/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(113): Illuminate\Queue\Worker->pop(NULL, NULL, '120', 3, '20')
#10 /x/website/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(85): Illuminate\Queue\Worker->runNextJobForDaemon(NULL, NULL, '120', 3, '20')
#11 /x/website/vendor/laravel/framework/src/Illuminate/Queue/Console/WorkCommand.php(101): Illuminate\Queue\Worker->daemon(NULL, NULL, '120', 128, 3, '20')
#12 /x/website/vendor/laravel/framework/src/Illuminate/Queue/Console/WorkCommand.php(67): Illuminate\Queue\Console\WorkCommand->runWorker(NULL, NULL, '120', 128, true)
#13 [internal function]: Illuminate\Queue\Console\WorkCommand->fire()
#14 /x/website/vendor/laravel/framework/src/Illuminate/Container/Container.php(523): call_user_func_array(Array, Array)
#15 /x/website/vendor/laravel/framework/src/Illuminate/Console/Command.php(115): Illuminate\Container\Container->call(Array)
#16 /x/website/vendor/symfony/console/Symfony/Component/Console/Command/Command.php(257): Illuminate\Console\Command->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#17 /x/website/vendor/laravel/framework/src/Illuminate/Console/Command.php(101): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#18 /x/website/vendor/symfony/console/Symfony/Component/Console/Application.php(874): Illuminate\Console\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#19 /x/website/vendor/symfony/console/Symfony/Component/Console/Application.php(195): Symfony\Component\Console\Application->doRunCommand(Object(Illuminate\Queue\Console\WorkCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#20 /x/website/vendor/symfony/console/Symfony/Component/Console/Application.php(126): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#21 /x/website/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(94): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#22 /x/website/artisan(36): Illuminate\Foundation\Console\Kernel->handle(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#23 {main}
I'm wondering if the problem might be caused by several workers going for the same job. Is that possible or is there some sort of mutex to control this?
What else might cause this?
The queued command was taking too long and the problem was caused by the TTR value on the tube in beanstalkd, but it's not necessary to change that value.
In a nutshell, beanstalkd will keep the job reserved only for a maximum period of time (up to the TTR) and then it will assume that something has gone wrong and return the job back to the ready state.
Instead, it's possible to periodically touch the job to reset the reservation timer.
In Laravel, I've added this to my App\Commands\Command class and I periodically call it inside of loops on long running jobs.
public function touch()
{
if (method_exists($this->job, 'getPheanstalk')) {
$this->job->getPheanstalk()->touch($this->job->getPheanstalkJob());
}
}