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HDFS-5496. Make replication queue initialization asynchronous. Contributed by Vinay. 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-5535@1552109 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Jing Zhao 2013-12-18 21:30:37 +00:00
parent d33d83b698
commit 788fca4124
7 changed files with 195 additions and 89 deletions
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9
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/LightWeightGSet.java
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@ -244,13 +244,14 @@ public class LightWeightGSet<K, E extends K> implements GSet<K, E> {
out.println("\n]");
}
private class SetIterator implements Iterator<E> {
public class SetIterator implements Iterator<E> {
/** The starting modification for fail-fast. */
private int iterModification = modification;
/** The current index of the entry array. */
private int index = -1;
private LinkedElement cur = null;
private LinkedElement next = nextNonemptyEntry();
private boolean trackModification = true;
/** Find the next nonempty entry starting at (index + 1). */
private LinkedElement nextNonemptyEntry() {
@ -259,7 +260,7 @@ public class LightWeightGSet<K, E extends K> implements GSet<K, E> {
}
private void ensureNext() {
if (modification != iterModification) {
if (trackModification && modification != iterModification) {
throw new ConcurrentModificationException("modification=" + modification
+ " != iterModification = " + iterModification);
}
@ -304,6 +305,10 @@ public class LightWeightGSet<K, E extends K> implements GSet<K, E> {
iterModification++;
cur = null;
}
public void setTrackModification(boolean trackModification) {
this.trackModification = trackModification;
}
}
/**

3
hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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@ -242,6 +242,9 @@ Trunk (Unreleased)
HDFS-5629. Support HTTPS in JournalNode and SecondaryNameNode.
(Haohui Mai via jing9)
HDFS-5496. Make replication queue initialization asynchronous. (Vinay via
jing9)
OPTIMIZATIONS
HDFS-5349. DNA_CACHE and DNA_UNCACHE should be by blockId only. (cmccabe)

4
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
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@ -398,7 +398,9 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
public static final int DFS_BLOCK_INVALIDATE_LIMIT_DEFAULT = 1000;
public static final String DFS_DEFAULT_MAX_CORRUPT_FILES_RETURNED_KEY = "dfs.corruptfilesreturned.max";
public static final int DFS_DEFAULT_MAX_CORRUPT_FILES_RETURNED = 500;
/* Maximum number of blocks to process for initializing replication queues */
public static final String DFS_BLOCK_MISREPLICATION_PROCESSING_LIMIT = "dfs.block.misreplication.processing.limit";
public static final int DFS_BLOCK_MISREPLICATION_PROCESSING_LIMIT_DEFAULT = 10000;
public static final String DFS_CLIENT_READ_SHORTCIRCUIT_KEY = "dfs.client.read.shortcircuit";
public static final boolean DFS_CLIENT_READ_SHORTCIRCUIT_DEFAULT = false;
public static final String DFS_CLIENT_READ_SHORTCIRCUIT_SKIP_CHECKSUM_KEY = "dfs.client.read.shortcircuit.skip.checksum";

114
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
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@ -229,6 +229,22 @@ public class BlockManager {
*/
private boolean shouldPostponeBlocksFromFuture = false;
/**
* Process replication queues asynchronously to allow namenode safemode exit
* and failover to be faster. HDFS-5496
*/
private Daemon replicationQueuesInitializer = null;
/**
* Number of blocks to process asychronously for replication queues
* initialization once aquired the namesystem lock. Remaining blocks will be
* processed again after aquiring lock again.
*/
private int numBlocksPerIteration;
/**
* Progress of the Replication queues initialisation.
*/
private double replicationQueuesInitProgress = 0.0;
/** for block replicas placement */
private BlockPlacementPolicy blockplacement;
@ -305,6 +321,9 @@ public class BlockManager {
this.maxNumBlocksToLog =
conf.getLong(DFSConfigKeys.DFS_MAX_NUM_BLOCKS_TO_LOG_KEY,
DFSConfigKeys.DFS_MAX_NUM_BLOCKS_TO_LOG_DEFAULT);
this.numBlocksPerIteration = conf.getInt(
DFSConfigKeys.DFS_BLOCK_MISREPLICATION_PROCESSING_LIMIT,
DFSConfigKeys.DFS_BLOCK_MISREPLICATION_PROCESSING_LIMIT_DEFAULT);
LOG.info("defaultReplication = " + defaultReplication);
LOG.info("maxReplication = " + maxReplication);
@ -2319,11 +2338,63 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
*/
public void processMisReplicatedBlocks() {
assert namesystem.hasWriteLock();
long nrInvalid = 0, nrOverReplicated = 0, nrUnderReplicated = 0, nrPostponed = 0,
nrUnderConstruction = 0;
stopReplicationInitializer();
neededReplications.clear();
for (BlockInfo block : blocksMap.getBlocks()) {
replicationQueuesInitializer = new Daemon() {
@Override
public void run() {
try {
processMisReplicatesAsync();
} catch (InterruptedException ie) {
LOG.info("Interrupted while processing replication queues.");
} catch (Exception e) {
LOG.error("Error while processing replication queues async", e);
}
}
};
replicationQueuesInitializer.setName("Replication Queue Initializer");
replicationQueuesInitializer.start();
}
/*
* Stop the ongoing initialisation of replication queues
*/
private void stopReplicationInitializer() {
if (replicationQueuesInitializer != null) {
replicationQueuesInitializer.interrupt();
try {
replicationQueuesInitializer.join();
} catch (final InterruptedException e) {
LOG.warn("Interrupted while waiting for replicationQueueInitializer. Returning..");
return;
} finally {
replicationQueuesInitializer = null;
}
}
}
/*
* Since the BlocksMapGset does not throw the ConcurrentModificationException
* and supports further iteration after modification to list, there is a
* chance of missing the newly added block while iterating. Since every
* addition to blocksMap will check for mis-replication, missing mis-replication
* check for new blocks will not be a problem.
*/
private void processMisReplicatesAsync() throws InterruptedException {
long nrInvalid = 0, nrOverReplicated = 0;
long nrUnderReplicated = 0, nrPostponed = 0, nrUnderConstruction = 0;
long startTimeMisReplicatedScan = Time.now();
Iterator<BlockInfo> blocksItr = blocksMap.getBlocks().iterator();
long totalBlocks = blocksMap.size();
replicationQueuesInitProgress = 0;
long totalProcessed = 0;
while (namesystem.isRunning() && !Thread.currentThread().isInterrupted()) {
int processed = 0;
namesystem.writeLockInterruptibly();
try {
while (processed < numBlocksPerIteration && blocksItr.hasNext()) {
BlockInfo block = blocksItr.next();
MisReplicationResult res = processMisReplicatedBlock(block);
if (LOG.isTraceEnabled()) {
LOG.trace("block " + block + ": " + res);
@ -2350,14 +2421,44 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
default:
throw new AssertionError("Invalid enum value: " + res);
}
processed++;
}
totalProcessed += processed;
// there is a possibility that if any of the blocks deleted/added during
// initialisation, then progress might be different.
replicationQueuesInitProgress = Math.min((double) totalProcessed
/ totalBlocks, 1.0);
if (!blocksItr.hasNext()) {
LOG.info("Total number of blocks = " + blocksMap.size());
LOG.info("Number of invalid blocks = " + nrInvalid);
LOG.info("Number of under-replicated blocks = " + nrUnderReplicated);
LOG.info("Number of over-replicated blocks = " + nrOverReplicated +
((nrPostponed > 0) ? ( " (" + nrPostponed + " postponed)") : ""));
LOG.info("Number of over-replicated blocks = " + nrOverReplicated
+ ((nrPostponed > 0) ? (" (" + nrPostponed + " postponed)") : ""));
LOG.info("Number of blocks being written = " + nrUnderConstruction);
NameNode.stateChangeLog
.info("STATE* Replication Queue initialization "
+ "scan for invalid, over- and under-replicated blocks "
+ "completed in " + (Time.now() - startTimeMisReplicatedScan)
+ " msec");
break;
}
} finally {
namesystem.writeUnlock();
}
}
if (Thread.currentThread().isInterrupted()) {
LOG.info("Interrupted while processing replication queues.");
}
}
/**
* Get the progress of the Replication queues initialisation
*
* @return Returns values between 0 and 1 for the progress.
*/
public double getReplicationQueuesInitProgress() {
return replicationQueuesInitProgress;
}
/**
@ -3308,6 +3409,7 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
}
public void shutdown() {
stopReplicationInitializer();
blocksMap.close();
}
}

16
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlocksMap.java
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@ -22,6 +22,7 @@ import java.util.Iterator;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.util.GSet;
import org.apache.hadoop.util.LightWeightGSet;
import org.apache.hadoop.util.LightWeightGSet.SetIterator;
/**
* This class maintains the map from a block to its metadata.
@ -62,7 +63,20 @@ class BlocksMap {
BlocksMap(int capacity) {
// Use 2% of total memory to size the GSet capacity
this.capacity = capacity;
this.blocks = new LightWeightGSet<Block, BlockInfo>(capacity);
this.blocks = new LightWeightGSet<Block, BlockInfo>(capacity) {
@Override
public Iterator<BlockInfo> iterator() {
SetIterator iterator = new SetIterator();
/*
* Not tracking any modifications to set. As this set will be used
* always under FSNameSystem lock, modifications will not cause any
* ConcurrentModificationExceptions. But there is a chance of missing
* newly added elements during iteration.
*/
iterator.setTrackModification(false);
return iterator;
}
};
}

65
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
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@ -483,6 +483,9 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
private final boolean haEnabled;
/** flag indicating whether replication queues have been initialized */
boolean initializedReplQueues = false;
/**
* Whether the namenode is in the middle of starting the active service
*/
@ -914,8 +917,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
try {
nnResourceChecker = new NameNodeResourceChecker(conf);
checkAvailableResources();
assert safeMode != null &&
!safeMode.isPopulatingReplQueues();
assert safeMode != null && !isPopulatingReplQueues();
StartupProgress prog = NameNode.getStartupProgress();
prog.beginPhase(Phase.SAFEMODE);
prog.setTotal(Phase.SAFEMODE, STEP_AWAITING_REPORTED_BLOCKS,
@ -971,10 +973,10 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
blockManager.clearQueues();
blockManager.processAllPendingDNMessages();
if (!isInSafeMode() ||
(isInSafeMode() && safeMode.isPopulatingReplQueues())) {
// Only need to re-process the queue, If not in SafeMode.
if (!isInSafeMode()) {
LOG.info("Reprocessing replication and invalidation queues");
blockManager.processMisReplicatedBlocks();
initializeReplQueues();
}
if (LOG.isDebugEnabled()) {
@ -1016,6 +1018,15 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
}
}
/**
* Initialize replication queues.
*/
private void initializeReplQueues() {
LOG.info("initializing replication queues");
blockManager.processMisReplicatedBlocks();
initializedReplQueues = true;
}
/**
* @return Whether the namenode is transitioning to active state and is in the
* middle of the {@link #startActiveServices()}
@ -1061,6 +1072,9 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
}
cacheManager.deactivate();
blockManager.getDatanodeManager().setShouldSendCachingCommands(false);
// Don't want to keep replication queues when not in Active.
blockManager.clearQueues();
initializedReplQueues = false;
} finally {
writeUnlock();
}
@ -4548,7 +4562,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
private int safeReplication;
/** threshold for populating needed replication queues */
private double replQueueThreshold;
// internal fields
/** Time when threshold was reached.
* <br> -1 safe mode is off
@ -4566,8 +4579,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
private int blockReplQueueThreshold;
/** time of the last status printout */
private long lastStatusReport = 0;
/** flag indicating whether replication queues have been initialized */
boolean initializedReplQueues = false;
/** Was safemode entered automatically because available resources were low. */
private boolean resourcesLow = false;
/** Should safemode adjust its block totals as blocks come in */
@ -4627,7 +4638,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
*
* @see SafeModeInfo
*/
private SafeModeInfo(boolean resourcesLow, boolean isReplQueuesInited) {
private SafeModeInfo(boolean resourcesLow) {
this.threshold = 1.5f; // this threshold can never be reached
this.datanodeThreshold = Integer.MAX_VALUE;
this.extension = Integer.MAX_VALUE;
@ -4636,7 +4647,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
this.blockTotal = -1;
this.blockSafe = -1;
this.resourcesLow = resourcesLow;
this.initializedReplQueues = isReplQueuesInited;
enter();
reportStatus("STATE* Safe mode is ON.", true);
}
@ -4650,13 +4660,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
return this.reached >= 0;
}
/**
* Check if we are populating replication queues.
*/
private synchronized boolean isPopulatingReplQueues() {
return initializedReplQueues;
}
/**
* Enter safe mode.
*/
@ -4703,21 +4706,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
}
}
/**
* Initialize replication queues.
*/
private synchronized void initializeReplQueues() {
LOG.info("initializing replication queues");
assert !isPopulatingReplQueues() : "Already initialized repl queues";
long startTimeMisReplicatedScan = now();
blockManager.processMisReplicatedBlocks();
initializedReplQueues = true;
NameNode.stateChangeLog.info("STATE* Replication Queue initialization "
+ "scan for invalid, over- and under-replicated blocks "
+ "completed in " + (now() - startTimeMisReplicatedScan)
+ " msec");
}
/**
* Check whether we have reached the threshold for
* initializing replication queues.
@ -4765,7 +4753,8 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
if (smmthread == null && needEnter()) {
enter();
// check if we are ready to initialize replication queues
if (canInitializeReplQueues() && !isPopulatingReplQueues()) {
if (canInitializeReplQueues() && !isPopulatingReplQueues()
&& !haEnabled) {
initializeReplQueues();
}
reportStatus("STATE* Safe mode ON.", false);
@ -4790,7 +4779,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
}
// check if we are ready to initialize replication queues
if (canInitializeReplQueues() && !isPopulatingReplQueues()) {
if (canInitializeReplQueues() && !isPopulatingReplQueues() && !haEnabled) {
initializeReplQueues();
}
}
@ -5100,11 +5089,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
if (!shouldPopulateReplQueues()) {
return false;
}
// safeMode is volatile, and may be set to null at any time
SafeModeInfo safeMode = this.safeMode;
if (safeMode == null)
return true;
return safeMode.isPopulatingReplQueues();
return initializedReplQueues;
}
private boolean shouldPopulateReplQueues() {
@ -5224,7 +5209,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
getEditLog().logSyncAll();
}
if (!isInSafeMode()) {
safeMode = new SafeModeInfo(resourcesLow, isPopulatingReplQueues());
safeMode = new SafeModeInfo(resourcesLow);
return;
}
if (resourcesLow) {

9
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/NameNodeAdapter.java
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@ -228,15 +228,10 @@ public class NameNodeAdapter {
}
/**
* @return true if safemode is not running, or if safemode has already
* initialized the replication queues
* @return Replication queue initialization status
*/
public static boolean safeModeInitializedReplQueues(NameNode nn) {
SafeModeInfo smi = nn.getNamesystem().getSafeModeInfoForTests();
if (smi == null) {
return true;
}
return smi.initializedReplQueues;
return nn.getNamesystem().isPopulatingReplQueues();
}
public static File getInProgressEditsFile(StorageDirectory sd, long startTxId) {