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From Kosala Dissanayake <>
Subject Re: questions on task, threads and workers
Date Mon, 02 Feb 2015 23:37:10 GMT
1. The default number of tasks for an executor thread is 1. So if you just
specify the parallelism for a bolt as 3, you will have 3 executor threads.
Since the default num of tasks for an executor thread is 1, this means you
will get 3 tasks.

You can increase the number of tasks for an executor thread from the
default 1 by using setNumTasks.

2. I don't think that's possible.

3. No. The number of workers is just the number of processes to which
executors can be allocated. If you have less workers, more executors will
be assigned to each worker and vice versa.
a pretty good introduction to these concepts

On Mon, Feb 2, 2015 at 9:54 AM, clay teahouse <>

> Hi,
> I have a few simple questions.
> 1)In storm .9.x, what is the default value for the bolt num tasks?
> According to the docs, the parallelism hint no longer sets the number of
> tasks, but the number of executor threads.
> 2)What happens if the number of tasks is less than the number of threads?
> Should I assume this results in idle threads?
> 3)Does the number of workers multiplies the number of tasks and threads?
> feedback appreciated,
> Clay

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