Author: cutting
Date: Fri Feb 9 11:51:24 2007
New Revision: 505462
URL: http://svn.apache.org/viewvc?view=rev&rev=505462
Log:
HADOOP-983. Improve HDFS client's handling of dead datanodes. Contributed by
Raghu.
Modified:
lucene/hadoop/trunk/CHANGES.txt
lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DFSClient.java
Modified: lucene/hadoop/trunk/CHANGES.txt
URL:
http://svn.apache.org/viewvc/lucene/hadoop/trunk/CHANGES.txt?view=diff&rev=505462&r1=505461&r2=505462
==============================================================================
--- lucene/hadoop/trunk/CHANGES.txt (original)
+++ lucene/hadoop/trunk/CHANGES.txt Fri Feb 9 11:51:24 2007
@@ -19,6 +19,10 @@
Also rename utility class Metrics to MetricsUtil.
(David Bowen & Nigel Daley via cutting)
+ 6. HADOOP-893. Improve HDFS client's handling of dead datanodes.
+ The set is no longer reset with each block, but rather is now
+ maintained for the life of an open file. (Raghu Angadi via cutting)
+
Branch 0.11 - unreleased
Modified: lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DFSClient.java
URL:
http://svn.apache.org/viewvc/lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DFSClient.java?view=diff&rev=505462&r1=505461&r2=505462
==============================================================================
--- lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DFSClient.java (original)
+++ lucene/hadoop/trunk/src/java/org/apache/hadoop/dfs/DFSClient.java Fri Feb
9 11:51:24 2007
@@ -496,6 +496,7 @@
private long pos = 0;
private long filelen = 0;
private long blockEnd = -1;
+ private TreeSet<DatanodeInfo> deadNodes = new TreeSet<DatanodeInfo>();
/**
*/
@@ -565,7 +566,7 @@
* Open a DataInputStream to a DataNode so that it can be read from.
* We get block ID and the IDs of the destinations at startup, from
the namenode.
*/
- private synchronized DatanodeInfo blockSeekTo(long target, TreeSet
deadNodes) throws IOException {
+ private synchronized DatanodeInfo blockSeekTo(long target) throws
IOException {
if (target >= filelen) {
throw new IOException("Attempted to read past end of file");
}
@@ -600,10 +601,9 @@
//
// Connect to best DataNode for desired Block, with potential
offset
//
- int failures = 0;
DatanodeInfo chosenNode = null;
while (s == null) {
- DNAddrPair retval = chooseDataNode(targetBlock, deadNodes);
+ DNAddrPair retval = chooseDataNode(targetBlock);
chosenNode = retval.info;
InetSocketAddress targetAddr = retval.addr;
@@ -685,7 +685,7 @@
int result = -1;
if (pos < filelen) {
if (pos > blockEnd) {
- currentNode = blockSeekTo(pos, new TreeSet());
+ currentNode = blockSeekTo(pos);
}
result = blockStream.read();
if (result >= 0) {
@@ -705,14 +705,10 @@
}
if (pos < filelen) {
int retries = 2;
- TreeSet deadNodes = null;
while (retries > 0) {
try {
if (pos > blockEnd) {
- if (deadNodes == null) {
- deadNodes = new TreeSet();
- }
- currentNode = blockSeekTo(pos, deadNodes);
+ currentNode = blockSeekTo(pos);
}
int realLen = Math.min(len, (int) (blockEnd - pos + 1));
int result = blockStream.read(buf, off, realLen);
@@ -723,7 +719,6 @@
} catch (IOException e) {
LOG.warn("DFS Read: " + StringUtils.stringifyException(e));
blockEnd = -1;
- if (deadNodes == null) { deadNodes = new TreeSet(); }
if (currentNode != null) { deadNodes.add(currentNode); }
if (--retries == 0) {
throw e;
@@ -735,7 +730,7 @@
}
- private DNAddrPair chooseDataNode(int blockId, TreeSet deadNodes)
+ private DNAddrPair chooseDataNode(int blockId)
throws IOException {
int failures = 0;
while (true) {
@@ -757,7 +752,7 @@
Thread.sleep(3000);
} catch (InterruptedException iex) {
}
- deadNodes.clear();
+ deadNodes.clear(); //2nd option is to remove only nodes[blockId]
openInfo();
failures++;
continue;
@@ -770,10 +765,9 @@
//
// Connect to best DataNode for desired Block, with potential offset
//
- TreeSet deadNodes = new TreeSet();
Socket dn = null;
while (dn == null) {
- DNAddrPair retval = chooseDataNode(blockId, deadNodes);
+ DNAddrPair retval = chooseDataNode(blockId);
DatanodeInfo chosenNode = retval.info;
InetSocketAddress targetAddr = retval.addr;
@@ -900,11 +894,16 @@
* If another node could not be found, then returns false.
*/
public synchronized boolean seekToNewSource(long targetPos) throws
IOException {
- TreeSet excludeNodes = new TreeSet();
- excludeNodes.add(currentNode);
- String oldNodeID = currentNode.getStorageID();
- DatanodeInfo newNode = blockSeekTo(targetPos, excludeNodes);
- if (!oldNodeID.equals(newNode.getStorageID())) {
+ boolean markedDead = deadNodes.contains(currentNode);
+ deadNodes.add(currentNode);
+ DatanodeInfo oldNode = currentNode;
+ DatanodeInfo newNode = blockSeekTo(targetPos);
+ if ( !markedDead ) {
+ /* remove it from deadNodes. blockSeekTo could have cleared
+ * deadNodes and added currentNode again. Thats ok. */
+ deadNodes.remove(oldNode);
+ }
+ if (!oldNode.getStorageID().equals(newNode.getStorageID())) {
currentNode = newNode;
return true;
} else {
