Good catch, Taras! +1 for balanced Rendezvous AF instead of Fair AF.
On Wed, Mar 15, 2017 at 1:29 PM, Taras Ledkov <[email protected]> wrote: > 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]> 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] > > 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 >> >> >> >> -- >> View this message in context: http://apache-ignite-users.705 >> 18.x6.nabble.com/Same-Affinity-For-Same-Key-On-All-Caches- >> tp10829p11006.html >> Sent from the Apache Ignite Users mailing list archive at Nabble.com. >> > > > > -- > Taras Ledkov > Mail-To: [email protected] > > -- Best regards, Andrey V. Mashenkov
