Top 10 Uses For A Message Queue
We’ve
been working with, building, and evangelising message queues for the
last year, and it’s no secret that we think they’re awesome. We believe
message queues are a vital component to any architecture or application,
and here are ten reasons why:
- Decoupling
It’s
extremely difficult to predict, at the start of a project, what the
future needs of the project will be. By introducing a layer in between
processes, message queues create an implicit, data-based interface that
both processes implement. This allows you to extend and modify these
processes independently, by simply ensuring they adhere to the same
interface requirements.
- Redundancy
Sometimes
processes fail when processing data. Unless that data is persisted,
it’s lost forever. Queues mitigate this by persisting data until it has
been fully processed. The put-get-delete paradigm, which many message
queues use, requires a process to explicitly indicate that it has
finished processing a message before the message is removed from the
queue, ensuring your data is kept safe until you’re done with it.
- Scalability
Because
message queues decouple your processes, it’s easy to scale up the rate
with which messages are added to the queue or processed; simply add
another process. No code needs to be changed, no configurations need to
be tweaked. Scaling is as simple as adding more power.
- Elasticity & Spikability
When
your application hits the front page of Hacker News, you’re going to
see unusual levels of traffic. Your application needs to be able to keep
functioning with this increased load, but the traffic is anomaly, not
the standard; it’s wasteful to have enough resources on standby to
handle these spikes. Message queues will allow beleaguered components to
struggle through the increased load, instead of getting overloaded with
requests and failing completely. Check out our Spikability blog post for more information about this.
- Resiliency
When
part of your architecture fails, it doesn’t need to take the entire
system down with it. Message queues decouple processes, so if a process
that is processing messages from the queue fails, messages can still be
added to the queue to be processed when the system recovers. This
ability to accept requests that will be retried or processed at a later
date is often the difference between an inconvenienced customer and a
frustrated customer.
- Delivery Guarantees
The
redundancy provided by message queues guarantees that a message will be
processed eventually, so long as a process is reading the queue. On top
of that, IronMQ provides an only-delivered-once guarantee. No matter
how many processes are pulling data from the queue, each message will
only be processed a single time. This is made possible because
retrieving a message "reserves" that message, temporarily removing it
from the queue. Unless the client specifically states that it‘s finished
with that message, the message will be placed back on the queue to be
processed after a configurable amount of time.
- Ordering Guarantees
In
a lot of situations, the order with which data is processed is
important. Message queues are inherently ordered, and capable of
providing guarantees that data will be processed in a specific order.
IronMQ guarantees that messages will be processed using FIFO (first in,
first out), so the order in which messages are placed on a queue is the
order in which they‘ll be retrieved from it.
- Buffering
In
any non-trivial system, there are going to be components that require
different processing times. For example, it takes less time to upload an
image than it does to apply a filter to it. Message queues help these
tasks operate at peak efficiency by offering a buffer layer--the process
writing to the queue can write as fast as it’s able to, instead of
being constrained by the readiness of the process reading from the
queue. This buffer helps control and optimise the speed with which data
flows through your system.
- Understanding Data Flow
In
a distributed system, getting an overall sense of how long user actions
take to complete and why is a huge problem. Message queues, through the
rate with which they are processed, help to easily identify
under-performing processes or areas where the data flow is not optimal.
- Asynchronous Communication
A
lot of times, you don’t want to or need to process a message
immediately. Message queues enable asynchronous processing, which allows
you to put a message on the queue without processing it immediately.
Queue up as many messages as you like, then process them at your
leisure.
We
believe these ten reasons make queues the best form of communication
between processes or applications. We’ve spent a year building and
learning from IronMQ, and our customers are doing amazing things with
message queues. Queues are the key to the powerful, distributed
applications that can leverage all the power that the cloud has to
offer.
If you‘d like to get started with an efficient, reliable, and hosted message queue today, check out IronMQ. If you’d like to connect with our engineers about how queues could fit into your application, they’re always available at get.iron.io/chat.
原文地址
消息队列的优势,布布扣,bubuko.com
消息队列的优势
原文：http://www.cnblogs.com/xuelu/p/3841028.html
