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HBASE-26308 Sum of multiplier of cost functions is not populated properly when we have a shortcut for trigger #3710

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Merged
huaxiangsun merged 2 commits into from
Oct 21, 2021
Merged

HBASE-26308 Sum of multiplier of cost functions is not populated properly when we have a shortcut for trigger #3710

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HBASE-26308 Sum of multiplier of cost functions is not populated prop…
clarax Sep 29, 2021
470ee6f
Move to after init the cost functions.
clarax Sep 29, 2021
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49 changes: 28 additions & 21 deletions ...alancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -132,7 +132,7 @@ public class StochasticLoadBalancer extends BaseLoadBalancer {
private List<CandidateGenerator> candidateGenerators;
private List<CostFunction> costFunctions; // FindBugs: Wants this protected; IS2_INCONSISTENT_SYNC
// To save currently configed sum of multiplier. Defaulted at 1 for cases that carry high cost
private float sumMultiplier = 1.0f;
private float sumMultiplier;
// to save and report costs to JMX
private double curOverallCost = 0d;
private double[] tempFunctionCosts;
Expand Down Expand Up @@ -248,11 +248,12 @@ protected void loadConf(Configuration conf) {
curFunctionCosts = new double[costFunctions.size()];
tempFunctionCosts = new double[costFunctions.size()];

LOG.info("Loaded config; maxSteps=" + maxSteps + ", runMaxSteps=" + runMaxSteps,
", stepsPerRegion=" + stepsPerRegion +
", maxRunningTime=" + maxRunningTime + ", isByTable=" + isByTable + ", CostFunctions=" +
Arrays.toString(getCostFunctionNames()) + " etc.");
}
LOG.info(
"Loaded config; maxSteps=" + maxSteps + ", runMaxSteps=" + runMaxSteps +
", stepsPerRegion=" + stepsPerRegion +
", maxRunningTime=" + maxRunningTime + ", isByTable=" + isByTable +
", CostFunctions=" + Arrays.toString(getCostFunctionNames()) +
" , sum of multiplier of cost functions = " + sumMultiplier + " etc."); }

@Override
public void updateClusterMetrics(ClusterMetrics st) {
Expand Down Expand Up @@ -345,33 +346,27 @@ boolean needsBalance(TableName tableName, BalancerClusterState cluster) {
return false;
}
if (areSomeRegionReplicasColocated(cluster)) {
LOG.info("Running balancer because at least one server hosts replicas of the same region.");
LOG.info("Running balancer because at least one server hosts replicas of the same region." +
" function cost={}", functionCost());
return true;
}

if (idleRegionServerExist(cluster)){
LOG.info("Running balancer because cluster has idle server(s).");
LOG.info("Running balancer because at least one server hosts replicas of the same region." +
"regionReplicaRackCostFunction={}", regionReplicaRackCostFunction.cost());
LOG.info("Running balancer because cluster has idle server(s)."+
" function cost={}", functionCost());
return true;
}

sumMultiplier = 0.0f;
double total = 0.0;
for (CostFunction c : costFunctions) {
float multiplier = c.getMultiplier();
double cost = c.cost();
if (!c.isNeeded()) {
LOG.trace("{} not needed", c.getClass().getSimpleName());
continue;
}
total += cost * multiplier;
sumMultiplier += multiplier;
total += c.cost() * c.getMultiplier();
}
if (sumMultiplier <= 0) {
LOG.error("At least one cost function needs a multiplier > 0. For example, set "
+ "hbase.master.balancer.stochastic.regionCountCost to a positive value or default");
return false;
}

boolean balanced = (total / sumMultiplier < minCostNeedBalance);
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@Apache9 Apache9 Oct 1, 2021

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We do not update sumMultiplier but use it directly? It could be zero here?

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@clarax clarax Oct 6, 2021

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It is moved up to the earlier stage before needsBalance is called so the short cut for idle server or cohosted replicas wouldn't get the wrong sum.


if (balanced) {
Expand Down Expand Up @@ -435,6 +430,18 @@ protected List<RegionPlan> balanceTable(TableName tableName, Map<ServerName,

initCosts(cluster);

sumMultiplier = 0;
for (CostFunction c : costFunctions) {
if(c.isNeeded()) {
sumMultiplier += c.getMultiplier();
}
}
if (sumMultiplier <= 0) {
LOG.error("At least one cost function needs a multiplier > 0. For example, set "
+ "hbase.master.balancer.stochastic.regionCountCost to a positive value or default");
return null;
}

double currentCost = computeCost(cluster, Double.MAX_VALUE);
curOverallCost = currentCost;
System.arraycopy(tempFunctionCosts, 0, curFunctionCosts, 0, curFunctionCosts.length);
Expand Down Expand Up @@ -598,8 +605,8 @@ private String functionCost() {
builder.append(", ");
double cost = c.cost();
builder.append("imbalance=" + cost);
if (cost < minCostNeedBalance) {
builder.append(", balanced");
if (cost >= minCostNeedBalance) {
builder.append(", need balance");
}
} else {
builder.append("not needed");
Expand Down