| /* |
| * 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.accumulo.tserver; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.accumulo.core.dataImpl.KeyExtent; |
| import org.apache.accumulo.core.util.ComparablePair; |
| import org.apache.accumulo.tserver.tablet.Tablet; |
| |
| import com.google.common.collect.Ordering; |
| |
| /** |
| * Computes the N tablets that have the highest deltas for a given monotonically increasing counter. |
| */ |
| public abstract class BusiestTracker { |
| |
| private Map<KeyExtent,Long> lastCounts = Collections.emptyMap(); |
| private final int numBusiestTabletsToLog; |
| |
| BusiestTracker(int numBusiestTabletsToLog) { |
| this.numBusiestTabletsToLog = numBusiestTabletsToLog; |
| } |
| |
| protected abstract long extractCount(Tablet tablet); |
| |
| public List<ComparablePair<Long,KeyExtent>> computeBusiest(Collection<Tablet> tablets) { |
| |
| HashMap<KeyExtent,Long> counts = new HashMap<>(); |
| |
| ArrayList<ComparablePair<Long,KeyExtent>> tabletsWithDelta = new ArrayList<>(); |
| |
| for (Tablet tablet : tablets) { |
| KeyExtent extent = tablet.getExtent(); |
| |
| // only get the count once to ensure consistency in the case of multiple threads |
| long count = extractCount(tablet); |
| |
| if (count == 0) |
| continue; |
| |
| counts.put(extent, count); |
| |
| long lastCount = lastCounts.getOrDefault(extent, 0L); |
| |
| // if a tablet leaves a tserver and comes back, then its count will be reset. This could make |
| // lastCount higher than the current count. That is why lastCount > count is checked below. |
| long delta = (lastCount > count) ? count : count - lastCount; |
| |
| // handle case where tablet had no activity |
| if (delta > 0) |
| tabletsWithDelta.add(new ComparablePair<>(delta, extent)); |
| } |
| |
| lastCounts = counts; |
| |
| return Ordering.natural().greatestOf(tabletsWithDelta, numBusiestTabletsToLog); |
| } |
| |
| static BusiestTracker newBusiestIngestTracker(int numBusiestTabletsToLog) { |
| return new BusiestTracker(numBusiestTabletsToLog) { |
| @Override |
| protected long extractCount(Tablet tablet) { |
| return tablet.totalIngest(); |
| } |
| }; |
| } |
| |
| static BusiestTracker newBusiestQueryTracker(int numBusiestTabletsToLog) { |
| return new BusiestTracker(numBusiestTabletsToLog) { |
| @Override |
| protected long extractCount(Tablet tablet) { |
| return tablet.totalQueries(); |
| } |
| }; |
| } |
| } |