Folks,

I worked on issue https://issues.apache.org/jira/browse/IGNITE-3018 that is related to performance of Rendezvous AF.

But Wang/Jenkins hash integer hash distribution is worse then MD5. So, i try to use simple partition balancer close
to Fair AF for Rendezvous AF.

Take a look at the heatmaps of distributions at the issue. e.g.:
- Compare of current Rendezvous AF and new Rendezvous AF based of Wang/Jenkins hash: https://issues.apache.org/jira/secure/attachment/12858701/004.png - Compare of current Rendezvous AF and new Rendezvous AF based of Wang/Jenkins hash with partition balancer: https://issues.apache.org/jira/secure/attachment/12858690/balanced.004.png

When the balancer is enabled the distribution of partitions by nodes looks like close to even distribution but in this case there is not guarantee that a partition doesn't move from one node to another
when node leave topology.
It is not guarantee but we try to minimize it because sorted array of nodes is used (like in for pure-Rendezvous AF).

I think we can use new fast Rendezvous AF and use 'useBalancer' flag instead of Fair AF.

On 03.03.2017 1:56, Denis Magda wrote:
What??? Unbelievable. It sounds like a design flaw to me. Any ideas how to fix?

—
Denis

On Mar 2, 2017, at 2:43 PM, Valentin Kulichenko <[email protected] <mailto:[email protected]>> wrote:

Adding back the dev list.

Folks,

Are there any opinions on the problem discussed here? Do we really need FairAffinityFunction if it can't guarantee cross-cache collocation?

-Val

On Thu, Mar 2, 2017 at 2:41 PM, vkulichenko <[email protected] <mailto:[email protected]>> wrote:

    Hi Alex,

    I see your point. Can you please outline its advantages vs rendezvous
    function?

    In my view issue discussed here makes it pretty much useless in vast
    majority of use cases, and very error-prone in all others.

    -Val



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