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*
* 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.regionserver.compactions;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Random;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.regionserver.StoreConfigInformation;
import org.apache.hadoop.hbase.regionserver.StoreFile;
import org.apache.hadoop.hbase.regionserver.StoreUtils;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.Collections2;
/**
* The default algorithm for selecting files for compaction.
* Combines the compaction configuration and the provisional file selection that
* it's given to produce the list of suitable candidates for compaction.
*/
@InterfaceAudience.Private
public class RatioBasedCompactionPolicy extends CompactionPolicy {
private static final Log LOG = LogFactory.getLog(RatioBasedCompactionPolicy.class);
public RatioBasedCompactionPolicy(Configuration conf,
StoreConfigInformation storeConfigInfo) {
super(conf, storeConfigInfo);
}
private ArrayList<StoreFile> getCurrentEligibleFiles(
ArrayList<StoreFile> candidateFiles, final List<StoreFile> filesCompacting) {
// candidates = all storefiles not already in compaction queue
if (!filesCompacting.isEmpty()) {
// exclude all files older than the newest file we're currently
// compacting. this allows us to preserve contiguity (HBASE-2856)
StoreFile last = filesCompacting.get(filesCompacting.size() - 1);
int idx = candidateFiles.indexOf(last);
Preconditions.checkArgument(idx != -1);
candidateFiles.subList(0, idx + 1).clear();
}
return candidateFiles;
}
public List<StoreFile> preSelectCompactionForCoprocessor(
final Collection<StoreFile> candidates, final List<StoreFile> filesCompacting) {
return getCurrentEligibleFiles(new ArrayList<StoreFile>(candidates), filesCompacting);
}
/**
* @param candidateFiles candidate files, ordered from oldest to newest. All files in store.
* @return subset copy of candidate list that meets compaction criteria
* @throws java.io.IOException
*/
public CompactionRequest selectCompaction(Collection<StoreFile> candidateFiles,
final List<StoreFile> filesCompacting, final boolean isUserCompaction,
final boolean mayUseOffPeak, final boolean forceMajor) throws IOException {
// Preliminary compaction subject to filters
ArrayList<StoreFile> candidateSelection = new ArrayList<StoreFile>(candidateFiles);
// Stuck and not compacting enough (estimate). It is not guaranteed that we will be
// able to compact more if stuck and compacting, because ratio policy excludes some
// non-compacting files from consideration during compaction (see getCurrentEligibleFiles).
int futureFiles = filesCompacting.isEmpty() ? 0 : 1;
boolean mayBeStuck = (candidateFiles.size() - filesCompacting.size() + futureFiles)
>= storeConfigInfo.getBlockingFileCount();
candidateSelection = getCurrentEligibleFiles(candidateSelection, filesCompacting);
LOG.debug("Selecting compaction from " + candidateFiles.size() + " store files, " +
filesCompacting.size() + " compacting, " + candidateSelection.size() +
" eligible, " + storeConfigInfo.getBlockingFileCount() + " blocking");
// If we can't have all files, we cannot do major anyway
boolean isAllFiles = candidateFiles.size() == candidateSelection.size();
if (!(forceMajor && isAllFiles)) {
candidateSelection = skipLargeFiles(candidateSelection);
isAllFiles = candidateFiles.size() == candidateSelection.size();
}
// Try a major compaction if this is a user-requested major compaction,
// or if we do not have too many files to compact and this was requested as a major compaction
boolean isTryingMajor = (forceMajor && isAllFiles && isUserCompaction)
|| (((forceMajor && isAllFiles) || isMajorCompaction(candidateSelection))
&& (candidateSelection.size() < comConf.getMaxFilesToCompact()));
// Or, if there are any references among the candidates.
boolean isAfterSplit = StoreUtils.hasReferences(candidateSelection);
if (!isTryingMajor && !isAfterSplit) {
// We're are not compacting all files, let's see what files are applicable
candidateSelection = filterBulk(candidateSelection);
candidateSelection = applyCompactionPolicy(candidateSelection, mayUseOffPeak, mayBeStuck);
candidateSelection = checkMinFilesCriteria(candidateSelection);
}
candidateSelection = removeExcessFiles(candidateSelection, isUserCompaction, isTryingMajor);
// Now we have the final file list, so we can determine if we can do major/all files.
isAllFiles = (candidateFiles.size() == candidateSelection.size());
CompactionRequest result = new CompactionRequest(candidateSelection);
result.setOffPeak(!candidateSelection.isEmpty() && !isAllFiles && mayUseOffPeak);
result.setIsMajor(isTryingMajor && isAllFiles, isAllFiles);
return result;
}
/**
* @param candidates pre-filtrate
* @return filtered subset
* exclude all files above maxCompactSize
* Also save all references. We MUST compact them
*/
private ArrayList<StoreFile> skipLargeFiles(ArrayList<StoreFile> candidates) {
int pos = 0;
while (pos < candidates.size() && !candidates.get(pos).isReference()
&& (candidates.get(pos).getReader().length() > comConf.getMaxCompactSize())) {
++pos;
}
if (pos > 0) {
LOG.debug("Some files are too large. Excluding " + pos
+ " files from compaction candidates");
candidates.subList(0, pos).clear();
}
return candidates;
}
/**
* @param candidates pre-filtrate
* @return filtered subset
* exclude all bulk load files if configured
*/
private ArrayList<StoreFile> filterBulk(ArrayList<StoreFile> candidates) {
candidates.removeAll(Collections2.filter(candidates,
new Predicate<StoreFile>() {
@Override
public boolean apply(StoreFile input) {
return input.excludeFromMinorCompaction();
}
}));
return candidates;
}
/**
* @param candidates pre-filtrate
* @return filtered subset
* take upto maxFilesToCompact from the start
*/
private ArrayList<StoreFile> removeExcessFiles(ArrayList<StoreFile> candidates,
boolean isUserCompaction, boolean isMajorCompaction) {
int excess = candidates.size() - comConf.getMaxFilesToCompact();
if (excess > 0) {
if (isMajorCompaction && isUserCompaction) {
LOG.debug("Warning, compacting more than " + comConf.getMaxFilesToCompact() +
" files because of a user-requested major compaction");
} else {
LOG.debug("Too many admissible files. Excluding " + excess
+ " files from compaction candidates");
candidates.subList(comConf.getMaxFilesToCompact(), candidates.size()).clear();
}
}
return candidates;
}
/**
* @param candidates pre-filtrate
* @return filtered subset
* forget the compactionSelection if we don't have enough files
*/
private ArrayList<StoreFile> checkMinFilesCriteria(ArrayList<StoreFile> candidates) {
int minFiles = comConf.getMinFilesToCompact();
if (candidates.size() < minFiles) {
if(LOG.isDebugEnabled()) {
LOG.debug("Not compacting files because we only have " + candidates.size() +
" files ready for compaction. Need " + minFiles + " to initiate.");
}
candidates.clear();
}
return candidates;
}
/**
* @param candidates pre-filtrate
* @return filtered subset
* -- Default minor compaction selection algorithm:
* choose CompactSelection from candidates --
* First exclude bulk-load files if indicated in configuration.
* Start at the oldest file and stop when you find the first file that
* meets compaction criteria:
* (1) a recently-flushed, small file (i.e. <= minCompactSize)
* OR
* (2) within the compactRatio of sum(newer_files)
* Given normal skew, any newer files will also meet this criteria
* <p/>
* Additional Note:
* If fileSizes.size() >> maxFilesToCompact, we will recurse on
* compact(). Consider the oldest files first to avoid a
* situation where we always compact [end-threshold,end). Then, the
* last file becomes an aggregate of the previous compactions.
*
* normal skew:
*
* older ----> newer (increasing seqID)
* _
* | | _
* | | | | _
* --|-|- |-|- |-|---_-------_------- minCompactSize
* | | | | | | | | _ | |
* | | | | | | | | | | | |
* | | | | | | | | | | | |
*/
ArrayList<StoreFile> applyCompactionPolicy(ArrayList<StoreFile> candidates,
boolean mayUseOffPeak, boolean mayBeStuck) throws IOException {
if (candidates.isEmpty()) {
return candidates;
}
// we're doing a minor compaction, let's see what files are applicable
int start = 0;
double ratio = comConf.getCompactionRatio();
if (mayUseOffPeak) {
ratio = comConf.getCompactionRatioOffPeak();
LOG.info("Running an off-peak compaction, selection ratio = " + ratio);
}
// get store file sizes for incremental compacting selection.
final int countOfFiles = candidates.size();
long[] fileSizes = new long[countOfFiles];
long[] sumSize = new long[countOfFiles];
for (int i = countOfFiles - 1; i >= 0; --i) {
StoreFile file = candidates.get(i);
fileSizes[i] = file.getReader().length();
// calculate the sum of fileSizes[i,i+maxFilesToCompact-1) for algo
int tooFar = i + comConf.getMaxFilesToCompact() - 1;
sumSize[i] = fileSizes[i]
+ ((i + 1 < countOfFiles) ? sumSize[i + 1] : 0)
- ((tooFar < countOfFiles) ? fileSizes[tooFar] : 0);
}
while (countOfFiles - start >= comConf.getMinFilesToCompact() &&
fileSizes[start] > Math.max(comConf.getMinCompactSize(),
(long) (sumSize[start + 1] * ratio))) {
++start;
}
if (start < countOfFiles) {
LOG.info("Default compaction algorithm has selected " + (countOfFiles - start)
+ " files from " + countOfFiles + " candidates");
} else if (mayBeStuck) {
// We may be stuck. Compact the latest files if we can.
int filesToLeave = candidates.size() - comConf.getMinFilesToCompact();
if (filesToLeave >= 0) {
start = filesToLeave;
}
}
candidates.subList(0, start).clear();
return candidates;
}
/*
* @param filesToCompact Files to compact. Can be null.
* @return True if we should run a major compaction.
*/
public boolean isMajorCompaction(final Collection<StoreFile> filesToCompact)
throws IOException {
boolean result = false;
long mcTime = getNextMajorCompactTime(filesToCompact);
if (filesToCompact == null || filesToCompact.isEmpty() || mcTime == 0) {
return result;
}
// TODO: Use better method for determining stamp of last major (HBASE-2990)
long lowTimestamp = StoreUtils.getLowestTimestamp(filesToCompact);
long now = System.currentTimeMillis();
if (lowTimestamp > 0l && lowTimestamp < (now - mcTime)) {
// Major compaction time has elapsed.
long cfTtl = this.storeConfigInfo.getStoreFileTtl();
if (filesToCompact.size() == 1) {
// Single file
StoreFile sf = filesToCompact.iterator().next();
Long minTimestamp = sf.getMinimumTimestamp();
long oldest = (minTimestamp == null)
? Long.MIN_VALUE
: now - minTimestamp.longValue();
if (sf.isMajorCompaction() &&
(cfTtl == HConstants.FOREVER || oldest < cfTtl)) {
if (LOG.isDebugEnabled()) {
LOG.debug("Skipping major compaction of " + this +
" because one (major) compacted file only and oldestTime " +
oldest + "ms is < ttl=" + cfTtl);
}
} else if (cfTtl != HConstants.FOREVER && oldest > cfTtl) {
LOG.debug("Major compaction triggered on store " + this +
", because keyvalues outdated; time since last major compaction " +
(now - lowTimestamp) + "ms");
result = true;
}
} else {
if (LOG.isDebugEnabled()) {
LOG.debug("Major compaction triggered on store " + this +
"; time since last major compaction " + (now - lowTimestamp) + "ms");
}
result = true;
}
}
return result;
}
/**
* Used calculation jitter
*/
private final Random random = new Random();
/**
* @param filesToCompact
* @return When to run next major compaction
*/
public long getNextMajorCompactTime(final Collection<StoreFile> filesToCompact) {
// default = 24hrs
long ret = comConf.getMajorCompactionPeriod();
if (ret > 0) {
// default = 20% = +/- 4.8 hrs
double jitterPct = comConf.getMajorCompactionJitter();
if (jitterPct > 0) {
long jitter = Math.round(ret * jitterPct);
// deterministic jitter avoids a major compaction storm on restart
Integer seed = StoreUtils.getDeterministicRandomSeed(filesToCompact);
if (seed != null) {
// Synchronized to ensure one user of random instance at a time.
double rnd = -1;
synchronized (this) {
this.random.setSeed(seed);
rnd = this.random.nextDouble();
}
ret += jitter - Math.round(2L * jitter * rnd);
} else {
ret = 0; // If seed is null, then no storefiles == no major compaction
}
}
}
return ret;
}
/**
* @param compactionSize Total size of some compaction
* @return whether this should be a large or small compaction
*/
public boolean throttleCompaction(long compactionSize) {
return compactionSize > comConf.getThrottlePoint();
}
public boolean needsCompaction(final Collection<StoreFile> storeFiles,
final List<StoreFile> filesCompacting) {
int numCandidates = storeFiles.size() - filesCompacting.size();
return numCandidates >= comConf.getMinFilesToCompact();
}
}