[GitHub] [hbase] huaxiangsun commented on a change in pull request #2003: HBASE-24633 Remove data locality and StoreFileCostFunction for replic…

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huaxiangsun commented on a change in pull request #2003:
URL: https://github.com/apache/hbase/pull/2003#discussion_r454031142



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File path: hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
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@@ -1462,8 +1473,14 @@ protected double getCostFromRl(BalancerRegionLoad rl) {
     }
 
     @Override
-    protected double getCostFromRl(BalancerRegionLoad rl) {
-      return rl.getStorefileSizeMB();
+    protected double getCostFromRl(BalancerRegionLoad rl, boolean isPrimaryRegion) {
+      // Do not count replica region's file size, as replica regions serve very little
+      // read requests, this may be changed if there are enough data from production showing

Review comment:
       As I wrote in the comments, all these factors really impacts system performance.  From one of the production clusters' stats, < 0.01% of requests goes to replica regions, which means most of regions are cold at Region servers. That is the reason I want to remove this factors from balancer. Agreed with you that things could be different with others, make it configurable makes more sense. If it is ok with you, I want to drop this change from this patch and creates a separate issue to track it, probably with a test case as well.




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