saintstack commented on a change in pull request #3356:
URL: https://github.com/apache/hbase/pull/3356#discussion_r668085556
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -303,54 +303,55 @@ private String getBalanceReason(double total, double
sumMultiplier) {
boolean needsBalance(TableName tableName, BalancerClusterState cluster) {
ClusterLoadState cs = new ClusterLoadState(cluster.clusterState);
if (cs.getNumServers() < MIN_SERVER_BALANCE) {
- if (LOG.isDebugEnabled()) {
- LOG.debug("Not running balancer because only " + cs.getNumServers()
+ LOG.info("Not running balancer because only " + cs.getNumServers()
+ " active regionserver(s)");
- }
sendRejectionReasonToRingBuffer(() -> "The number of RegionServers " +
cs.getNumServers() +
" < MIN_SERVER_BALANCE(" + MIN_SERVER_BALANCE + ")", null);
return false;
}
if (areSomeRegionReplicasColocated(cluster)) {
+ LOG.info("Running balancer because at least one server hosts replicas of
the same region.");
Review comment:
good
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -303,54 +303,55 @@ private String getBalanceReason(double total, double
sumMultiplier) {
boolean needsBalance(TableName tableName, BalancerClusterState cluster) {
ClusterLoadState cs = new ClusterLoadState(cluster.clusterState);
if (cs.getNumServers() < MIN_SERVER_BALANCE) {
- if (LOG.isDebugEnabled()) {
- LOG.debug("Not running balancer because only " + cs.getNumServers()
+ LOG.info("Not running balancer because only " + cs.getNumServers()
+ " active regionserver(s)");
- }
sendRejectionReasonToRingBuffer(() -> "The number of RegionServers " +
cs.getNumServers() +
" < MIN_SERVER_BALANCE(" + MIN_SERVER_BALANCE + ")", null);
return false;
}
if (areSomeRegionReplicasColocated(cluster)) {
+ LOG.info("Running balancer because at least one server hosts replicas of
the same region.");
return true;
}
if (idleRegionServerExist(cluster)){
+ LOG.info("Running balancer because cluster has idle server(s).");
Review comment:
And idea is that a rebalance would make it so the load is distributed?
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -423,8 +424,9 @@ private long calculateMaxSteps(BalancerClusterState
cluster) {
maxSteps);
}
}
- LOG.info("start StochasticLoadBalancer.balancer, initCost=" + currentCost
+ ", functionCost="
- + functionCost() + " computedMaxSteps: " + computedMaxSteps);
+ LOG.info("Start StochasticLoadBalancer.balancer, initial weighted average
imbalance={}, "
Review comment:
Could we say anything here on what these values mean ? For the operator?
(Need a ',' after the functionCost).
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -303,54 +303,55 @@ private String getBalanceReason(double total, double
sumMultiplier) {
boolean needsBalance(TableName tableName, BalancerClusterState cluster) {
ClusterLoadState cs = new ClusterLoadState(cluster.clusterState);
if (cs.getNumServers() < MIN_SERVER_BALANCE) {
- if (LOG.isDebugEnabled()) {
- LOG.debug("Not running balancer because only " + cs.getNumServers()
+ LOG.info("Not running balancer because only " + cs.getNumServers()
+ " active regionserver(s)");
- }
sendRejectionReasonToRingBuffer(() -> "The number of RegionServers " +
cs.getNumServers() +
" < MIN_SERVER_BALANCE(" + MIN_SERVER_BALANCE + ")", null);
return false;
}
if (areSomeRegionReplicasColocated(cluster)) {
+ LOG.info("Running balancer because at least one server hosts replicas of
the same region.");
return true;
}
if (idleRegionServerExist(cluster)){
+ LOG.info("Running balancer because cluster has idle server(s).");
return true;
}
+ sumMultiplier = 0.0f;
double total = 0.0;
- float sumMultiplier = 0.0f;
for (CostFunction c : costFunctions) {
float multiplier = c.getMultiplier();
- if (multiplier <= 0) {
- LOG.trace("{} not needed because multiplier is <= 0",
c.getClass().getSimpleName());
- continue;
- }
+ double cost = c.cost();
if (!c.isNeeded()) {
LOG.trace("{} not needed", c.getClass().getSimpleName());
continue;
}
+ total += cost * multiplier;
sumMultiplier += multiplier;
- total += c.cost() * multiplier;
+ }
+ if (sumMultiplier <= 0) {
+ LOG.error("At least one cost function needs a multiplier > 0. For
example, set "
Review comment:
Good
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -423,8 +424,9 @@ private long calculateMaxSteps(BalancerClusterState
cluster) {
maxSteps);
}
}
- LOG.info("start StochasticLoadBalancer.balancer, initCost=" + currentCost
+ ", functionCost="
- + functionCost() + " computedMaxSteps: " + computedMaxSteps);
+ LOG.info("Start StochasticLoadBalancer.balancer, initial weighted average
imbalance={}, "
Review comment:
imbalance?
(Looked it up... "lack of proportion or relation between corresponding
things." <= Nice)
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -303,54 +303,55 @@ private String getBalanceReason(double total, double
sumMultiplier) {
boolean needsBalance(TableName tableName, BalancerClusterState cluster) {
ClusterLoadState cs = new ClusterLoadState(cluster.clusterState);
if (cs.getNumServers() < MIN_SERVER_BALANCE) {
- if (LOG.isDebugEnabled()) {
- LOG.debug("Not running balancer because only " + cs.getNumServers()
+ LOG.info("Not running balancer because only " + cs.getNumServers()
+ " active regionserver(s)");
- }
sendRejectionReasonToRingBuffer(() -> "The number of RegionServers " +
cs.getNumServers() +
" < MIN_SERVER_BALANCE(" + MIN_SERVER_BALANCE + ")", null);
return false;
}
if (areSomeRegionReplicasColocated(cluster)) {
+ LOG.info("Running balancer because at least one server hosts replicas of
the same region.");
return true;
}
if (idleRegionServerExist(cluster)){
+ LOG.info("Running balancer because cluster has idle server(s).");
return true;
}
+ sumMultiplier = 0.0f;
double total = 0.0;
- float sumMultiplier = 0.0f;
for (CostFunction c : costFunctions) {
float multiplier = c.getMultiplier();
- if (multiplier <= 0) {
- LOG.trace("{} not needed because multiplier is <= 0",
c.getClass().getSimpleName());
- continue;
- }
+ double cost = c.cost();
if (!c.isNeeded()) {
LOG.trace("{} not needed", c.getClass().getSimpleName());
continue;
}
+ total += cost * multiplier;
sumMultiplier += multiplier;
- total += c.cost() * multiplier;
+ }
+ 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 <= 0 || sumMultiplier <= 0 ||
- (sumMultiplier > 0 && (total / sumMultiplier) < minCostNeedBalance);
+ boolean balanced = (total / sumMultiplier < minCostNeedBalance);
+
if (balanced) {
final double calculatedTotal = total;
- final double calculatedMultiplier = sumMultiplier;
- sendRejectionReasonToRingBuffer(() -> getBalanceReason(calculatedTotal,
calculatedMultiplier),
- costFunctions);
- }
- if (LOG.isDebugEnabled()) {
- LOG.debug("{} {}; total cost={}, sum multiplier={}; cost/multiplier to
need a balance is {}",
- balanced ? "Skipping load balancing because balanced" : "We need to
load balance",
- isByTable ? String.format("table (%s)", tableName) : "cluster",
- total, sumMultiplier, minCostNeedBalance);
- if (LOG.isTraceEnabled()) {
- LOG.trace("Balance decision detailed function costs={}",
functionCost());
- }
+ sendRejectionReasonToRingBuffer(() ->
+ getBalanceReason(calculatedTotal, sumMultiplier), costFunctions);
+ LOG.info("{} - skipping load balancing because weighted average
imbalance={} <= "
+ + "threshold({}). If you want more aggressive balancing, either
lower "
+ + "hbase.master.balancer.stochastic.minCostNeedBalance from {} or
increase the relative "
+ + "multiplier(s) of the specific cost function(s). functionCost={}",
Review comment:
Good
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -303,54 +302,54 @@ private String getBalanceReason(double total, double
sumMultiplier) {
boolean needsBalance(TableName tableName, BalancerClusterState cluster) {
ClusterLoadState cs = new ClusterLoadState(cluster.clusterState);
if (cs.getNumServers() < MIN_SERVER_BALANCE) {
- if (LOG.isDebugEnabled()) {
- LOG.debug("Not running balancer because only " + cs.getNumServers()
+ LOG.info("Not running balancer because only " + cs.getNumServers()
+ " active regionserver(s)");
- }
sendRejectionReasonToRingBuffer(() -> "The number of RegionServers " +
cs.getNumServers() +
" < MIN_SERVER_BALANCE(" + MIN_SERVER_BALANCE + ")", null);
return false;
}
if (areSomeRegionReplicasColocated(cluster)) {
+ LOG.info("Running balancer because at least one server hosts replicas of
the same region.");
return true;
}
if (idleRegionServerExist(cluster)){
+ LOG.info("Running balancer because cluster has idle server(s).");
return true;
}
+ sumMultiplier = 0.0f;
double total = 0.0;
- float sumMultiplier = 0.0f;
for (CostFunction c : costFunctions) {
float multiplier = c.getMultiplier();
- if (multiplier <= 0) {
- LOG.trace("{} not needed because multiplier is <= 0",
c.getClass().getSimpleName());
- continue;
- }
+ double cost = c.cost();
if (!c.isNeeded()) {
LOG.trace("{} not needed", c.getClass().getSimpleName());
continue;
}
+ total += cost * multiplier;
sumMultiplier += multiplier;
- total += c.cost() * multiplier;
+ }
+ if (sumMultiplier <= 0)
+ {
+ LOG.error("At least one cost function needs a multiplier > 0");
+ return false;
Review comment:
What about Seans' comment above?
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -470,17 +470,17 @@ private long calculateMaxSteps(BalancerClusterState
cluster) {
updateStochasticCosts(tableName, curOverallCost, curFunctionCosts);
if (initCost > currentCost) {
List<RegionPlan> plans = createRegionPlans(cluster);
- LOG.info("Finished computing new load balance plan. Computation took {}"
+
- " to try {} different iterations. Found a solution that moves " +
- "{} regions; Going from a computed cost of {}" +
- " to a new cost of {}", java.time.Duration.ofMillis(endTime -
startTime),
- step, plans.size(), initCost, currentCost);
+ LOG.info("Finished computing new load balance plan. Computation took {}
ms" +
+ " to try {} different iterations. Found a solution that moves " +
+ "{} regions; Going from a computed cost of {}" +
+ " to a new cost of {}. Move plan to be submitted to master to
execute",
+ endTime - startTime, step, plans.size(), initCost, currentCost);
sendRegionPlansToRingBuffer(plans, currentCost, initCost,
initFunctionTotalCosts, step);
return plans;
}
LOG.info("Could not find a better load balance plan. Tried {} different
configurations in " +
Review comment:
Was this addressed?
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -470,17 +470,17 @@ private long calculateMaxSteps(BalancerClusterState
cluster) {
updateStochasticCosts(tableName, curOverallCost, curFunctionCosts);
if (initCost > currentCost) {
List<RegionPlan> plans = createRegionPlans(cluster);
- LOG.info("Finished computing new load balance plan. Computation took {}"
+
- " to try {} different iterations. Found a solution that moves " +
- "{} regions; Going from a computed cost of {}" +
- " to a new cost of {}", java.time.Duration.ofMillis(endTime -
startTime),
- step, plans.size(), initCost, currentCost);
+ LOG.info("Finished computing new load balance plan. Computation took {}
ms" +
+ " to try {} different iterations. Found a solution that moves " +
+ "{} regions; Going from a computed cost of {}" +
+ " to a new cost of {}. Move plan to be submitted to master to
execute",
Review comment:
This addressed?
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -470,17 +470,17 @@ private long calculateMaxSteps(BalancerClusterState
cluster) {
updateStochasticCosts(tableName, curOverallCost, curFunctionCosts);
if (initCost > currentCost) {
List<RegionPlan> plans = createRegionPlans(cluster);
- LOG.info("Finished computing new load balance plan. Computation took {}"
+
- " to try {} different iterations. Found a solution that moves " +
- "{} regions; Going from a computed cost of {}" +
- " to a new cost of {}", java.time.Duration.ofMillis(endTime -
startTime),
- step, plans.size(), initCost, currentCost);
+ LOG.info("Finished computing new load balance plan. Computation took {}
ms" +
Review comment:
This addressed?
##########
File path:
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
##########
@@ -343,15 +343,15 @@ boolean needsBalance(TableName tableName,
BalancerClusterState cluster) {
sendRejectionReasonToRingBuffer(() -> getBalanceReason(calculatedTotal,
calculatedMultiplier),
costFunctions);
}
- if (LOG.isDebugEnabled()) {
- LOG.debug("{} {}; total cost={}, sum multiplier={}; cost/multiplier to
need a balance is {}",
- balanced ? "Skipping load balancing because balanced" : "We need to
load balance",
- isByTable ? String.format("table (%s)", tableName) : "cluster",
- total, sumMultiplier, minCostNeedBalance);
- if (LOG.isTraceEnabled()) {
- LOG.trace("Balance decision detailed function costs={}",
functionCost());
- }
+ LOG.info("{} {}; total cost={}, sum multiplier={}; cost/multiplier to need
a balance is {}",
+ balanced ? "Skipping load balancing because balanced" :
Review comment:
I was thinking either explaining terms or pointing to doc or elsewhere
where terms are explained and how the balancer machinations engage w/ them. Can
do in a later PR, yes. This one is a big improvement as is.
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