[infinispan-issues] [JBoss JIRA] (ISPN-4841) TopologyAwareConsistentHashFactory is slow for large cluster

[Takayoshi Kimura (JIRA)]

Takayoshi Kimura created ISPN-4841:
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             Summary: TopologyAwareConsistentHashFactory is slow for large cluster
                 Key: ISPN-4841
                 URL: https://issues.jboss.org/browse/ISPN-4841
             Project: Infinispan
          Issue Type: Enhancement
          Components: Core
    Affects Versions: 7.0.0.CR1
            Reporter: Takayoshi Kimura


A user observed 100% CPU usage for a long time on coordinator node when booting 500 nodes with 500 caches defined.

It looks like the TopologyAwareConsistentHashFactory performs O(n^2), it has double loop for all Machines. It takes 50 sec to compute rebalance with 1 cache 500 nodes. This calculation is performed on every cache, so it eats 25000 sec CPU times with 500 nodes 500 caches.

The hprof shows 90% of the time is consumed in the TopologyInfo.computeMaxSegmentsForMachine().




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