Laravel Artisan Queues - high cpu usage
I have set up queues in Laravel for my processing scripts. I am using beanstalkd and supervisord. There are 6 different tubes for different types of processing.
The issue is that for each tube, artisan is constantly spawning workers every second. The worker code seems to sleep for 1 second and then the worker thread uses 7-15% cpu, multiply this by 6 tubes... and I would like to have multiple workers per tube.. my cpu is being eaten up.
I tried changing the 1 second sleep to 10 seconds. This helps but there is still a huge cpu spike every 10 seconds when the workers wake back up. I am not even processing anything at this time because the queues are completely empty, it is simply the workers looking for something to do.
I also tested to see the cpu usage of laravel when I refreshed the page in a brower and that was hovering around 10%.. I am on a low end rackspace instance right now so that could explain it but still... it seems like the workers spin up a laravel instance every time they wake up.
Is there no way to solve this? Do I just have to put a lot of money into a more expensive server just to be able to listen to see if a job is ready?
EDIT:
Found a solution... it was to NOT use the artisan queue:listener or queue:work I looked into the queue code and there doesn't seem to be a way around this issue, it requires laravel to load every time a worker checks for more work to do.
Instead I wrote my own listener using pheanstalk. I am still using laravel to push things into the queue, then my custom listener is parsing the queue data and then triggering an artisan command to run.
Now my cpu usage for my listeners is under %0, the only time my cpu shoots up now is when it actually finds work to do and then triggers the command, I am fine with that.
Answer
The problem of high CPU is caused because the worker loads the complete framework everytime it checks for a job in the queue. In laravel 4.2, you can use php artisan queue:work --daemon. This will load the framework once and the checking/processing of jobs happen inside a while loop, which lets CPU breathe easy. You can find more about daemon worker in the official documentation: http://laravel.com/docs/queues#daemon-queue-worker.
However, this benefit comes with a drawback - you need special care when deploying the code and you have to take care of the database connections. Usually, long running database connections are disconnected.