[openstack-dev] blueprint amqp-rpc-fast-reply-queue

Mark McLoughlin markmc at redhat.com
Tue Jan 29 15:14:36 UTC 2013


On Tue, 2013-01-29 at 00:23 -0600, Ray Pekowski wrote:
> This is in regards to the comments in the code review for this blueprint:
> https://review.openstack.org/#/c/19721/
> This blueprint is blocked primarily due to backward compatibility issues.
> Russell Bryant posted in a different thread that RPC features are typically
> added in two releases.  The first to enable the receiving of message having
> the new feature.  The second to enable the sending of messages having the
> new feature.

I admit I haven't been following this conversation closely enough, but
that seems like a slight misunderstanding.

See https://review.openstack.org/17554

Russell did originally add a config option to allow enabling the new
format, but I said:

  Why would a user choose to enable the new format now? Isn't there
  basically no benefit until we start using the new format to do
  something interesting in H?

> My biggest concern is I don't want to wait two releases.  I propose that we
> add an unsupported option "unsupported_amqp_rpc_single_reply_queue" which
> enables this performance improvement feature.  This option would not be
> documented.  It would be removed from the next release when the feature
> becomes always enabled.

In this case, there is a (performance) benefit to using the new feature
so it probably does make sense to have an off-by-default feature which
we'd enable by default for the H release.

The config option should be documented though :)


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