From b4c3fe97638a4bcd4d950f6c571315d320ca47f3 Mon Sep 17 00:00:00 2001 From: Kahlil Oppenheimer Date: Tue, 6 Jun 2017 15:53:43 -0400 Subject: [PATCH] HBASE-18164 Fast locality computation in balancer - addendum handles NaN -Added new LocalityCostFunction and LocalityCandidateGenerator that cache localities of every region/rack combination and mappings of every region to its most local server and to its most local rack. -Made LocalityCostFunction incremental so that it only computes locality based on most recent region moves/swaps, rather than recomputing the locality of every region in the cluster at every iteration of the balancer -Changed locality cost function to reflect the ratio of: (Current locality) / (Best locality possible given current cluster) Signed-off-by: tedyu --- .../hbase/master/balancer/StochasticLoadBalancer.java | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java index 63ec0b50f93..ece91534759 100644 --- a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java +++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java @@ -1286,8 +1286,9 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { } // We normalize locality to be a score between 0 and 1.0 representing how good it - // is compared to how good it could be - locality /= bestLocality; + // is compared to how good it could be. If bestLocality is 0, assume locality is 100 + // (and the cost is 0) + locality = bestLocality == 0 ? 1 : locality / bestLocality; } @Override @@ -1298,7 +1299,7 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { return; } double localityDelta = getWeightedLocality(region, newEntity) - getWeightedLocality(region, oldEntity); - double normalizedDelta = localityDelta / bestLocality; + double normalizedDelta = bestLocality == 0 ? 0.0 : localityDelta / bestLocality; locality += normalizedDelta; }