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On 05/07/2010 03:59 PM, Jason Pellerin wrote:
<blockquote cite="mid:201005071559.07067.jpellerin@leapfrogonline.com"
type="cite">
<blockquote type="cite" style="color: rgb(0, 0, 0);">
<pre wrap="">Flow control acts like a more fine-grained channel.flow for publishers,
<span class="moz-txt-citetags">> </span>and like basic.qos for consumers; in each case, the receiving side
<span class="moz-txt-citetags">> </span>issues <b
class="moz-txt-star"><span class="moz-txt-tag">*</span>credit<span
class="moz-txt-tag">*</span></b>, which the sending side uses up by transferring
<span class="moz-txt-citetags">> </span>messages. To do something like a basic.get, a consumer issues a single
<span class="moz-txt-citetags">> </span>unit of <b
class="moz-txt-star"><span class="moz-txt-tag">*</span>credit<span
class="moz-txt-tag">*</span></b>, and waits for the single message to come in.
</pre>
</blockquote>
<pre wrap="">I hope I'm missing something, but this description jumped out at me as looking
like AMQP 1.0 is going to include one of (IMO) 0-10's biggest mistakes.
As someone using messaging mainly in web applications, basic.get is the best
thing in amqp. When response time matters, having a single command that polls
for a message and returns immediately if one isn't present is incredibly
useful. Replacing that with 2+ commands and replacing polling with waiting --
ouch.
</pre>
</blockquote>
<br>
Having a poll is just a matter of setting the properties. For example
Qpid<br>
supports a 'get()' opperation with AMQP 0-10. I have not worked through
the <br>
options in detail in 1-0, but it takes this one step further with not
only allowing a get(),<br>
but you can even do a get() in a single stateless call i.e. (open get()
close) in<br>
a single command sequence.<br>
<br>
This is particularly usefull for web-apps for example and better than
any<br>
previous version as no connection state needs to kept open as with all
previous<br>
versions.<br>
<br>
Carl.<br>
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