-
Notifications
You must be signed in to change notification settings - Fork 3.3k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
HBASE-25894 Improve the performance for region load and region count …
…related cost functions (#3276) Signed-off-by: Yi Mei <[email protected]>
- Loading branch information
Showing
7 changed files
with
245 additions
and
129 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
100 changes: 100 additions & 0 deletions
100
hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/DoubleArrayCost.java
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,100 @@ | ||
/** | ||
* Licensed to the Apache Software Foundation (ASF) under one | ||
* or more contributor license agreements. See the NOTICE file | ||
* distributed with this work for additional information | ||
* regarding copyright ownership. The ASF licenses this file | ||
* to you under the Apache License, Version 2.0 (the | ||
* "License"); you may not use this file except in compliance | ||
* with the License. You may obtain a copy of the License at | ||
* | ||
* http://www.apache.org/licenses/LICENSE-2.0 | ||
* | ||
* Unless required by applicable law or agreed to in writing, software | ||
* distributed under the License is distributed on an "AS IS" BASIS, | ||
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
* See the License for the specific language governing permissions and | ||
* limitations under the License. | ||
*/ | ||
package org.apache.hadoop.hbase.master.balancer; | ||
|
||
import java.util.function.Consumer; | ||
import org.apache.yetus.audience.InterfaceAudience; | ||
|
||
/** | ||
* A helper class to compute a scaled cost using | ||
* {@link org.apache.commons.math3.stat.descriptive.DescriptiveStatistics#DescriptiveStatistics()}. | ||
* It assumes that this is a zero sum set of costs. It assumes that the worst case possible is all | ||
* of the elements in one region server and the rest having 0. | ||
*/ | ||
@InterfaceAudience.Private | ||
final class DoubleArrayCost { | ||
|
||
private double[] costs; | ||
|
||
// computeCost call is expensive so we use this flag to indicate whether we need to recalculate | ||
// the cost by calling computeCost | ||
private boolean costsChanged; | ||
|
||
private double cost; | ||
|
||
void prepare(int length) { | ||
if (costs == null || costs.length != length) { | ||
costs = new double[length]; | ||
} | ||
} | ||
|
||
void setCosts(Consumer<double[]> consumer) { | ||
consumer.accept(costs); | ||
costsChanged = true; | ||
} | ||
|
||
double cost() { | ||
if (costsChanged) { | ||
cost = computeCost(costs); | ||
costsChanged = false; | ||
} | ||
return cost; | ||
} | ||
|
||
private static double computeCost(double[] stats) { | ||
double totalCost = 0; | ||
double total = getSum(stats); | ||
|
||
double count = stats.length; | ||
double mean = total / count; | ||
|
||
// Compute max as if all region servers had 0 and one had the sum of all costs. This must be | ||
// a zero sum cost for this to make sense. | ||
double max = ((count - 1) * mean) + (total - mean); | ||
|
||
// It's possible that there aren't enough regions to go around | ||
double min; | ||
if (count > total) { | ||
min = ((count - total) * mean) + ((1 - mean) * total); | ||
} else { | ||
// Some will have 1 more than everything else. | ||
int numHigh = (int) (total - (Math.floor(mean) * count)); | ||
int numLow = (int) (count - numHigh); | ||
|
||
min = (numHigh * (Math.ceil(mean) - mean)) + (numLow * (mean - Math.floor(mean))); | ||
|
||
} | ||
min = Math.max(0, min); | ||
for (int i = 0; i < stats.length; i++) { | ||
double n = stats[i]; | ||
double diff = Math.abs(mean - n); | ||
totalCost += diff; | ||
} | ||
|
||
double scaled = CostFunction.scale(min, max, totalCost); | ||
return scaled; | ||
} | ||
|
||
private static double getSum(double[] stats) { | ||
double total = 0; | ||
for (double s : stats) { | ||
total += s; | ||
} | ||
return total; | ||
} | ||
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.