Hi Changgeng, I think the first invocation will always be null, subsequent invocations should provide you the previous resource assignment. Are you saying its always null?.
thanks, Kishore G On Wed, Jun 24, 2015 at 3:42 PM, Changgeng Li <[email protected]> wrote: > Hello, > > We have a use case that when adding or removing a new node, we hope to > minimize the shuffle of partitions between nodes. I'm trying to implement a > customized rebalancer calculating the new resource assignment based on the > previous resource assignment. When a new node is added, just move some > partitions from existing node to the new node, and when a node is down, > move the partitions on this node to the other nodes. Partitions would not > move between two nodes if the both status are not changed. > > The documentation says: > In rebalance(), ... the third is the output of the previous invocation of > this method (if supported) ... > > During my testing I found the previous resource assignment passed in is > always null. my question is what "if supported" means here? Does the > rebalancer need to support something? > > > Any other suggestions are also welcome. > > Thanks, > Changgeng >
