Only one worker will claim your job. So it's one by one.
job in beanstalk gets created by a client with the "put" command. During its
life it can be in one of four states: "ready", "reserved", "delayed", or
"buried". After the put command, a job typically starts out ready. It waits in
the ready queue until a worker comes along and runs the "reserve" command. If
this job is next in the queue, it will be reserved for the worker. The worker
will execute the job; when it is finished the worker will send a "delete"
command to delete the job.
worker that wants to consume jobs from the queue uses "reserve", "delete",
"release", and "bury".