delayed_job 2.0

April 3, 2010 code , popular 2 min read

I’ve pushed out the delayed_job 2.0 gem from the Collective Idea fork on GitHub. See the changelog for a summary of changes, or see the full list changes.

Multiple Backends

One of the most significant changes was adding support for multiple backends. You can now use Active Record, MongoMapper, or DataMapper as backends for your job queue. See the README for more info.


The Active Record backend in delayed_job 2.0 is much faster (6x in the benchmarks I ran), primarily due to reversing the priority column and adding an index. Here are benchmarks for running 10,000 simple jobs on my laptop:

                      user     system      total        real
delayed_job 1.8.5 195.670000  14.020000  209.690000 (230.887172)
delayed_job 2.0    36.200000   0.940000  37.140000  ( 39.959233)

While we’re looking at benchmarks, here is how the current backends compare:

                     user     system      total        real
active_record      36.200000   0.940000  37.140000 ( 39.959233)
mongo_mapper       69.270000   3.220000  72.490000 ( 90.783220)
data_mapper       255.620000   2.880000 258.500000 (275.550383)

I have not done anything to optimize the mongo_mapper or data_mapper backend, so performance patches would be appreciated.


To take full advantage of the Active Record performance improvements, you’ll want to add an index:

add_index :delayed_jobs, [:priority, :run_at], :name => 'delayed_jobs_priority'

The only other issue that most people will run into is that all of the configuration options have been moved to Delayed::Worker. Here’s how to change the options now:

Delayed::Worker.destroy_failed_jobs = false   # Delayed::Job.destroy_failed_jobs = false
Delayed::Worker.max_attempts = 3              # Delayed::Job.const_set("MAX_ATTEMPTS", 3)
Delayed::Worker.max_run_time = 5.minutes      # Delayed::Job.const_set("MAX_RUN_TIME", 5.minutes)
Delayed::Worker.sleep_delay = 60              # Delayed::Worker.const_set("SLEEP", 60)

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avatar of Brandon Keepers I am Brandon Keepers, and I work at GitHub on making Open Source more approachable, effective, and ubiquitous. I tend to think like an engineer, work like an artist, dream like an astronaut, love like a human, and sleep like a baby.