Ah.. ok. Nice. That should work. Parallel dispatch on the client would work too.. using async.
On Fri, Jul 25, 2014 at 1:37 PM, Laing, Michael <michael.la...@nytimes.com> wrote: > We use IN (keeping the number down). The coordinator does parallel > dispatch AND applies ORDERED BY to the aggregate results, which we would > otherwise have to do ourselves. Anyway, worth it for us. > > ml > > > On Fri, Jul 25, 2014 at 1:24 PM, Kevin Burton <bur...@spinn3r.com> wrote: > >> Perhaps the best strategy is to have the datastax java-driver do this and >> I just wait or each result individually. This will give me parallel >> dispatch. >> >> >> On Fri, Jul 25, 2014 at 11:40 AM, Graham Sanderson <gra...@vast.com> >> wrote: >> >>> Of course the driver in question is allowed to be smarter and can do so >>> if use use a ? parameter for a list or even individual elements >>> >>> I'm not sure which if any drivers currently do this but we plan to >>> combine this with token aware routing in our scala driver in the future >>> >>> Sent from my iPhone >>> >>> On Jul 25, 2014, at 1:14 PM, DuyHai Doan <doanduy...@gmail.com> wrote: >>> >>> Nope. Select ... IN() sends one request to a coordinator. This >>> coordinator dispatch the request to 50 nodes as in your example and waits >>> for 50 responses before sending back the final result. As you can guess >>> this approach is not optimal since the global request latency is bound to >>> the slowest latency among 50 nodes. >>> >>> On the other hand if you use async feature from the native protocol, >>> you client will issue 50 requests in parallel and the answers arrive as >>> soon as they are fetched from different nodes. >>> >>> Clearly the only advantage of using IN() clause is ease of query. I >>> would advise to use IN() only when you have a "few" values, not 50. >>> >>> >>> On Fri, Jul 25, 2014 at 8:08 PM, Kevin Burton <bur...@spinn3r.com> >>> wrote: >>> >>>> Say I have about 50 primary keys I need to fetch. >>>> >>>> I'd like to use parallel dispatch. So that if I have 50 hosts, and >>>> each has record, I can read from all 50 at once. >>>> >>>> I assume cassandra does the right thing here ? I believe it does… at >>>> least from reading the docs but it's still a bit unclear. >>>> >>>> Kevin >>>> >>>> -- >>>> >>>> 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> >>>> >>>> >>> >> >> >> -- >> >> 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> >> >> > -- 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>
