Yes, your description is correct. A particular member's data would all be in one partition.
Broker partitions are just the unit of parallelism--think of each partition as a totally ordered log you can append to and read from. The consumption of one of these partition logs is single threaded. The guarantee is that all messages are added to a partition in the order they arrive. From the point of view of a single producer client this will also be the order in which they are sent. These messages are then delivered in this order to a consumer thread. Hope that helps. -Jay On Sun, Nov 25, 2012 at 7:54 PM, S Ahmed <sahmed1...@gmail.com> wrote: > The wiki states "Consider an application that would like to maintain an > aggregation of the number of profile visitors for each member. It would > like to send all profile visit events for a member to a particular > partition and, hence, have all updates for a member to appear in the same > stream for the same consumer thread." ( > http://incubator.apache.org/kafka/design.html) > > So say I have 5 broker servers, now my producer will send a message for a > particular profile page visit, with the default algorithm using > hash(member_id)%num_partitions > to figur out which broker server to send it it. > > So a particular members pageview messages will all go to a single server > then, is this the case? And therefore all the messages for a given user > will be in the correct order also right? > > So a consumer group that subscribes to the 'profile-page-view' topic will > consume page view related messages, is it possible to subscribe to a > particular broker partition also? > > Are broker partitions meant for cases when you want all messages to be > saved on the same node? >
