> builder.setBolt("MyBolt", new MyBolt(), 4).shuffleGrouping("MySpout"); i
> found this example but couldn't know why he use number 4 ?
This is the “parallelism hint” (the number of threads) for “MyBolt”. So in your
example there will be 4 threads executing “MyBolt” across the workers in your
cluster and the tuples from “MySpout” would be randomly distributed across all
of the 4 instances of your bolt.
Also see
http://storm.apache.org/releases/1.0.1/Understanding-the-parallelism-of-a-Storm-topology.html
From: sam mohel <[email protected]>
Reply-To: "[email protected]" <[email protected]>
Date: Monday, January 23, 2017 at 4:47 PM
To: "[email protected]" <[email protected]>
Subject: Re: simple question about grouping
excuse me , if i have single spout and single bolt and the bolt doing 2 process
so can i do like this
builder.setSpout("MySpout", new mySpout(), 1);
builder.setBolt("MyBolt", new MyBolt(), 4).shuffleGrouping("MySpout"); i found
this example but couldn't know why he use number 4 ?
On Mon, Jan 23, 2017 at 1:13 PM, sam mohel <[email protected]> wrote:
thanks for replying
On Mon, Jan 23, 2017 at 1:14 PM, Arun Mahadevan <[email protected]> wrote:
Grouping makes sense only when you have more than one task for a bolt. If your
bolt has more than one task, then the grouping will decide how the tuples from
the spout are distributed to the individual tasks of the bolt. (shuffe =
random, fields = keyed on some field and so on).
See http://storm.apache.org/releases/current/Concepts.html
Thanks,
Arun
From: sam mohel <[email protected]>
Reply-To: "[email protected]" <[email protected]>
Date: Monday, January 23, 2017 at 3:09 PM
To: "[email protected]" <[email protected]>, "[email protected]"
<[email protected]>
Subject: simple question about grouping
i have text file contains data . size of this file is 3.5 MB . My topology
consists of one spout and one bolt so is that possible to make all processing
in one bolt and in this case what is the role of grouping here ?
Thanks in advance
