You may have figured this out in the past 3 weeks since you sent your first note, but the answer to your question is that no, it's not currently possible to enable PFC selectively, though there are a few tweaks you can make individually.
PFC doesn't apply to consumers, so there is nothing you can set per-consumer. PFC can't be enabled/disabled on a per-destination basis (it's either on for the entire broker and all destinations within it, or not), but you can set per-destination limits at which it kicks in even if the broker as a whole hasn't hit its limit. By setting those limits for certain destinations but not others, you can cause some of them to be PFC'ed earlier and others not until the entire broker's memory store is full, but all destinations will be PFC'ed when the broker's memory store is full. There is no way to tell the broker to PFC certain destinations but allow others to keep sending messages after the whole-broker memory store is full (which presumably would lead to an OOM fairly quickly, so it's not clear you'd want it anyway). The closest you could come would be to set the memory store limit equal to the JVM size and then set per-destination limits on only some destinations; then your JVM would OOM before any of your unrestricted destinations could be PFC'ed. But again, I don't see why you'd want to disable PFC, since OOMing your broker sounds like a bad thing rather than a good thing. Producers can be individually flow controlled - sort of - but I think the wiki page you got your info from ( http://activemq.apache.org/producer-flow-control.html) is pretty misleading. The broker will kick in PFC at the same point no matter whether per-producer PFC is enabled, but this means something different than you think it does. When the broker PFCs an individual destination, any producers using per-producer PFC will block, because they're waiting for an ack that won't come until PFC ends. Any producers not using per-producer PFC will continue sending blindly; when the broker receives the next message from those producers, the broker will stop processing all messages on that connection (because it's got nowhere to put the message sent by the PFCed producer), including messages sent to destinations that are not PFCed and acks sent by consumers using that connection. (That can lead to deadlocks, as referenced by the wiki page.) Eventually the clients on that connection will fill the broker's TCP receive buffer and the client process's TCP send buffer, and they'll block on the send call - even though they are nominally asynchronous. So the result of disabling per-producer PFC isn't actually to disable PFC for that producer; it does the opposite, by ending up PFCing producers that shouldn't have been affected (as well as consumers, who should never be affected by PFC). Your consideration should be whether to enable per-producer PFC on all producers instead of just the default ones, not whether to disable it on all producers, which is why the wiki has instructions on how to do the former but not the latter. Tim On Wed, Apr 1, 2015 at 8:32 PM, Kevin Burton <bur...@spinn3r.com> wrote: > I have some consumers that I want to disable flow control on , and others > where I want it enabled . > > Is this possible? > > I was looking at how it was disabled by default on async unless you specify > a window, but that seems like a hack to me and probably prone to some > unknown issue I might run into. Maybe I’m wrong of course. > > -- > > Founder/CEO Spinn3r.com > Location: *San Francisco, CA* > blog: http://burtonator.wordpress.com > … or check out my Google+ profile > <https://plus.google.com/102718274791889610666/posts> > <http://spinn3r.com> >
