Well, the send to everyone and manually filter turned out to be a
really bad idea -- I guess the message gets copied too many times or
whatever. It gets an OOM error with a 512 MB heap for 10,000 clients.
So I'm still looking for a better way, whether it be general approach
or tuning to handle high number of selectors or topics.
Thanks,
Aaron
On Mon, Apr 27, 2009 at 11:04 PM, Aaron Mulder
<ammul...@alumni.princeton.edu> wrote:
> Let's say I have 100,000 stock tickers (or whatever) I want to track,
> each with a separate client.
>
> There seem to be two approaches -- putting them all in one topic and
> having each of the clients use a selector (ticker equivalent in a
> header property), or putting messages for each header on it's own
> topic and subscribing each consumer to one dedicated topic.
>
> When I try this, the performance stinks. With the selector approach
> it takes as long as like 10 minutes for 100,000 clients to connect
> (using the VM transport), I need more than 256 MB of heap (512 was
> fine but 384 might have been OK), and the message send/receive time
> seems to go up more or less linearly with the number of clients (like,
> .5 seconds for 1000 clients, 5s for 10,000 clients, 75s for 100,000
> clients, all for 1000 messages). My actual selector used two header
> properties, but you get the idea.
>
> With the topic approach, which I assumed would perform better on
> account of eliminating the selectors, the persistent store blew out
> file handles and crashed, so I disabled persistence for the test. (Is
> there a disk-based store that doesn't keep an open file for each
> topic?). With that out of the way, it seemed OK up to 10,000 clients
> (and up to 3x as fast for message send/receive), but isn't really able
> to connect 100,000 clients each to a different topic. Like, the first
> 40K took 20 minutes, and the it pretty much hit the limit of 512 heap
> and the next 2K took 15 minutes of which at least 12 was in GC, etc.
> I'm not sure how high I'm willing to push the heap, but over 1 GB
> seems out of line when I haven't sent any messages yet.
>
> Anyway, this wasn't really what I had hoped for. Is there some good
> way to customize the configuration to either handle ~100K selectors
> really optimally, or ~100K topics really optimally?
>
> Or would it just be better to have one topic where every client gets
> every message and manually discards the ones it doesn't care about? I
> haven't tried that yet.
>
> Thanks,
> Aaron
>
