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Hudson commented on HBASE-25739: -------------------------------- Results for branch master [build #264 on builds.a.o|https://ci-hadoop.apache.org/job/HBase/job/HBase%20Nightly/job/master/264/]: (x) *{color:red}-1 overall{color}* ---- details (if available): (/) {color:green}+1 general checks{color} -- For more information [see general report|https://ci-hadoop.apache.org/job/HBase/job/HBase%20Nightly/job/master/264/General_20Nightly_20Build_20Report/] (x) {color:red}-1 jdk8 hadoop3 checks{color} -- For more information [see jdk8 (hadoop3) report|https://ci-hadoop.apache.org/job/HBase/job/HBase%20Nightly/job/master/264/JDK8_20Nightly_20Build_20Report_20_28Hadoop3_29/] (x) {color:red}-1 jdk11 hadoop3 checks{color} -- For more information [see jdk11 report|https://ci-hadoop.apache.org/job/HBase/job/HBase%20Nightly/job/master/264/JDK11_20Nightly_20Build_20Report_20_28Hadoop3_29/] (/) {color:green}+1 source release artifact{color} -- See build output for details. (/) {color:green}+1 client integration test{color} > TableSkewCostFunction need to use aggregated deviation > ------------------------------------------------------ > > Key: HBASE-25739 > URL: https://issues.apache.org/jira/browse/HBASE-25739 > Project: HBase > Issue Type: Sub-task > Components: Balancer, master > Reporter: Clara Xiong > Assignee: Clara Xiong > Priority: Major > Fix For: 3.0.0-alpha-1 > > > TableSkewCostFunction uses the sum of the max deviation region per server for > all tables as the measure of unevenness. It doesn't work in a very common > scenario in operations. Say we have 100 regions on 50 nodes, two on each. We > add 50 new nodes and they have 0 each. The max deviation from the mean is 1, > compared to 99 in the worst case scenario of 100 regions on a single server. > The normalized cost is 1/99 = 0.011 < default threshold of 0.05. Balancer > wouldn't move. The proposal is to use aggregated deviation of the count per > region server to detect this scenario, generating a cost of 100/198 = 0.5 in > this case. -- This message was sent by Atlassian Jira (v8.3.4#803005)