风暴场分组 [英] Storm fields grouping

问题描述

我遇到以下情况:

• 有许多螺栓可以计算出不同的值
• 此值发送到可视化螺栓
• 可视化螺栓打开Web套接字并以某种方式发送要可视化的值

问题是，可视化螺栓始终是相同的，但是它会为每种类型的螺栓(其输入)发送带有不同标头的消息.例如:

• BoltSum计算总和
• BoltDif计算差异

• BoltMul计算多个

• 所有这些螺栓都使用VisualizationBolt进行可视化

• 在这种情况下，有3个VisualizationBolt实例

我的问题是，我应该创建3个独立的实例，其中每个实例都有一个线程，例如

builder.setBolt("forSum", new VisualizationBolt(),1).globalGrouping("bolt-sum");
builder.setBolt("forDif", new VisualizationBolt(),1).globalGrouping("bolt-dif");
builder.setBolt("forMul", new VisualizationBolt(),1).globalGrouping("bolt-mul");

还是应该执行以下操作

builder.setBolt("forAll", new VisualizationBolt(),3)
.fieldsGrouping("forSum", new Fields("type"))
.fieldsGrouping("forDif", new Fields("type"))
.fieldsGrouping("forMul", new Fields("type"));

并从每个先前的螺栓中发出类型，以便可以基于它们进行分组?

有什么优势?

此外，我是否应该期望每次螺栓总和都将到达第一个可视化螺栓，bolt-dif将到达第二个可视化螺栓，bolt-mul将会到达第三个可视化螺栓?他们不会混在一起吗?

我认为应该是这种情况，但是目前不在我的实现中，所以我不确定这是一个错误还是缺少某些东西?

解决方案

使用三个实例的第一种方法是正确的方法.使用fieldsGrouping不能不确保"sum"值进入"Sum-Visualization-Bolt"，并且sum/diff/mul值也不是唯一的(即，在不同的螺栓实例中)./p>

fieldGrouping的语义更加宽松:它仅保证，同一类型的所有元组将由单个螺栓实例处理，即永远不会这样，两个不同的螺栓实例将获得相同类型.

I'm having the following situation:

• There is a number of bolts that calculate different values
• This values are sent to visualization bolt
• Visualization bolt opens a web socket and sends values to be visualized somehow

The thing is, visualization bolt is always the same, but it sends a message with a different header for each type of bolt that can be its input. For example:

• BoltSum calculates sum
• BoltDif calculates difference

• BoltMul calculates multiple

• All this bolts use VisualizationBolt for visualization

• There are 3 instances of VisualizationBolt in this case

My question is, should I create 3 independent instances, where each instance will have one thread, e.g.

builder.setBolt("forSum", new VisualizationBolt(),1).globalGrouping("bolt-sum");
builder.setBolt("forDif", new VisualizationBolt(),1).globalGrouping("bolt-dif");
builder.setBolt("forMul", new VisualizationBolt(),1).globalGrouping("bolt-mul");

Or should I do the following

builder.setBolt("forAll", new VisualizationBolt(),3)
.fieldsGrouping("forSum", new Fields("type"))
.fieldsGrouping("forDif", new Fields("type"))
.fieldsGrouping("forMul", new Fields("type"));

And emit type from each of the previous bolts, so they can be grouped on based on it?

What are the advantages?

Also, should I expect that each and every time bolt-sum will go to first visualization bolt, bolt-dif will go to second visualization bolt and bolt-mul will go to third visualization bolt? They won't be mixed?

I think that that should be the case, but it currently isn't in my implementation, so I'm not sure if it's a bug or I'm missing something?

解决方案

The first approach using three instances is the correct approach. Using fieldsGrouping does not ensure, that "sum" values go to "Sum-Visualization-Bolt" and neither that sum/diff/mul values are distinct (ie, in different bolt instances).

The semantic of fieldGrouping is more relaxed: it only guarantees, that all tuples of the same type will be processed by a single bolt instance, ie, that it will never be the case, that two different bolt instances get the same type.

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