Author: suresh
Date: Fri Sep 21 05:47:03 2012
New Revision: 1388330
URL: http://svn.apache.org/viewvc?rev=1388330&view=rev
Log:
HDFS-3596. Improve FSEditLog pre-allocation in branch-1. Contributed by Colin
Patrick McCabe, backported by Jing Zhao.
Modified:
hadoop/common/branches/branch-1.1/CHANGES.txt
hadoop/common/branches/branch-1.1/src/hdfs/org/apache/hadoop/hdfs/server/namenode/FSEditLog.java
hadoop/common/branches/branch-1.1/src/test/org/apache/hadoop/hdfs/server/namenode/TestEditLog.java
Modified: hadoop/common/branches/branch-1.1/CHANGES.txt
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1.1/CHANGES.txt?rev=1388330&r1=1388329&r2=1388330&view=diff
==============================================================================
--- hadoop/common/branches/branch-1.1/CHANGES.txt (original)
+++ hadoop/common/branches/branch-1.1/CHANGES.txt Fri Sep 21 05:47:03 2012
@@ -341,6 +341,9 @@ Release 1.1.0 - 2012.09.16
HDFS-3466. Get HTTP kerberos principal from the web authentication keytab.
(omalley)
+ HDFS-3596. Improve FSEditLog pre-allocation in branch-1
+ (Colin Patrick McCabe, backported by Jing Zhao via suresh)
+
Release 1.0.4 - Unreleased
NEW FEATURES
Modified:
hadoop/common/branches/branch-1.1/src/hdfs/org/apache/hadoop/hdfs/server/namenode/FSEditLog.java
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1.1/src/hdfs/org/apache/hadoop/hdfs/server/namenode/FSEditLog.java?rev=1388330&r1=1388329&r2=1388330&view=diff
==============================================================================
---
hadoop/common/branches/branch-1.1/src/hdfs/org/apache/hadoop/hdfs/server/namenode/FSEditLog.java
(original)
+++
hadoop/common/branches/branch-1.1/src/hdfs/org/apache/hadoop/hdfs/server/namenode/FSEditLog.java
Fri Sep 21 05:47:03 2012
@@ -37,6 +37,8 @@ import java.lang.Math;
import java.nio.channels.FileChannel;
import java.nio.ByteBuffer;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.DatanodeID;
import org.apache.hadoop.hdfs.protocol.FSConstants;
@@ -55,6 +57,8 @@ import org.apache.hadoop.security.token.
*
*/
public class FSEditLog {
+ private static final Log LOG = LogFactory.getLog(FSEditLog.class);
+
private static final byte OP_INVALID = -1;
private static final byte OP_ADD = 0;
private static final byte OP_RENAME = 1; // rename
@@ -80,6 +84,8 @@ public class FSEditLog {
private static final byte OP_UPDATE_MASTER_KEY = 21; //update master key
private static int sizeFlushBuffer = 512*1024;
+ /** Preallocation length in bytes for writing edit log. */
+ static final int MIN_PREALLOCATION_LENGTH = 1024 * 1024;
private ArrayList<EditLogOutputStream> editStreams = null;
private FSImage fsimage = null;
@@ -121,13 +127,22 @@ public class FSEditLog {
* An implementation of the abstract class {@link EditLogOutputStream},
* which stores edits in a local file.
*/
- static private class EditLogFileOutputStream extends EditLogOutputStream {
+ static class EditLogFileOutputStream extends EditLogOutputStream {
+ /** Preallocation buffer, padded with OP_INVALID */
+ private static final ByteBuffer PREALLOCATION_BUFFER
+ = ByteBuffer.allocateDirect(MIN_PREALLOCATION_LENGTH);
+ static {
+ PREALLOCATION_BUFFER.position(0).limit(MIN_PREALLOCATION_LENGTH);
+ for(int i = 0; i < PREALLOCATION_BUFFER.capacity(); i++) {
+ PREALLOCATION_BUFFER.put(OP_INVALID);
+ }
+ }
+
private File file;
private FileOutputStream fp; // file stream for storing edit logs
private FileChannel fc; // channel of the file stream for sync
private DataOutputBuffer bufCurrent; // current buffer for writing
private DataOutputBuffer bufReady; // buffer ready for flushing
- static ByteBuffer fill = ByteBuffer.allocateDirect(512); // preallocation
EditLogFileOutputStream(File name) throws IOException {
super();
@@ -174,6 +189,8 @@ public class FSEditLog {
@Override
public void close() throws IOException {
+ LOG.info("closing edit log: position=" + fc.position() + ", editlog=" +
getName());
+
// close should have been called after all pending transactions
// have been flushed & synced.
int bufSize = bufCurrent.size();
@@ -185,11 +202,13 @@ public class FSEditLog {
bufCurrent.close();
bufReady.close();
- // remove the last INVALID marker from transaction log.
+ // remove any preallocated padding bytes from the transaction log.
fc.truncate(fc.position());
fp.close();
bufCurrent = bufReady = null;
+
+ LOG.info("close success: truncate to " + file.length() + ", editlog=" +
getName());
}
/**
@@ -199,7 +218,6 @@ public class FSEditLog {
@Override
void setReadyToFlush() throws IOException {
assert bufReady.size() == 0 : "previous data is not flushed yet";
- write(OP_INVALID); // insert end-of-file marker
DataOutputBuffer tmp = bufReady;
bufReady = bufCurrent;
bufCurrent = tmp;
@@ -216,7 +234,6 @@ public class FSEditLog {
bufReady.writeTo(fp); // write data to file
bufReady.reset(); // erase all data in the buffer
fc.force(false); // metadata updates not needed because of
preallocation
- fc.position(fc.position()-1); // skip back the end-of-file marker
}
/**
@@ -230,16 +247,26 @@ public class FSEditLog {
// allocate a big chunk of data
private void preallocate() throws IOException {
- long position = fc.position();
- if (position + 4096 >= fc.size()) {
- FSNamesystem.LOG.debug("Preallocating Edit log, current size " +
- fc.size());
- long newsize = position + 1024*1024; // 1MB
- fill.position(0);
- int written = fc.write(fill, newsize);
- FSNamesystem.LOG.debug("Edit log size is now " + fc.size() +
- " written " + written + " bytes " +
- " at offset " + newsize);
+ long size = fc.size();
+ int bufSize = bufReady.getLength();
+ long need = bufSize - (size - fc.position());
+ if (need <= 0) {
+ return;
+ }
+ long oldSize = size;
+ long total = 0;
+ long fillCapacity = PREALLOCATION_BUFFER.capacity();
+ while (need > 0) {
+ PREALLOCATION_BUFFER.position(0);
+ do {
+ size += fc.write(PREALLOCATION_BUFFER, size);
+ } while (PREALLOCATION_BUFFER.remaining() > 0);
+ need -= fillCapacity;
+ total += fillCapacity;
+ }
+ if(FSNamesystem.LOG.isDebugEnabled()) {
+ FSNamesystem.LOG.debug("Preallocated " + total + " bytes at the end of
" +
+ "the edit log (offset " + oldSize + ")");
}
}
Modified:
hadoop/common/branches/branch-1.1/src/test/org/apache/hadoop/hdfs/server/namenode/TestEditLog.java
URL:
http://svn.apache.org/viewvc/hadoop/common/branches/branch-1.1/src/test/org/apache/hadoop/hdfs/server/namenode/TestEditLog.java?rev=1388330&r1=1388329&r2=1388330&view=diff
==============================================================================
---
hadoop/common/branches/branch-1.1/src/test/org/apache/hadoop/hdfs/server/namenode/TestEditLog.java
(original)
+++
hadoop/common/branches/branch-1.1/src/test/org/apache/hadoop/hdfs/server/namenode/TestEditLog.java
Fri Sep 21 05:47:03 2012
@@ -76,6 +76,36 @@ public class TestEditLog extends TestCas
}
}
}
+
+ public void testEditLogPreallocation() throws IOException {
+ final File TEST_DIR =
+ new File(System.getProperty("test.build.data", "/tmp"));
+ final File TEST_EDITS = new File(TEST_DIR, "edit_log");
+
+ FSEditLog.EditLogFileOutputStream elfos = null;
+ try {
+ elfos = new FSEditLog.EditLogFileOutputStream(TEST_EDITS);
+ byte b[] = new byte[1024];
+ for (int i = 0; i < b.length; i++) {
+ b[i] = 0;
+ }
+ elfos.write(b);
+ elfos.setReadyToFlush();
+ elfos.flushAndSync();
+ assertEquals(FSEditLog.MIN_PREALLOCATION_LENGTH,
+ elfos.getFile().length());
+ for (int i = 0;
+ i < 2 * FSEditLog.MIN_PREALLOCATION_LENGTH / b.length; i++) {
+ elfos.write(b);
+ elfos.setReadyToFlush();
+ elfos.flushAndSync();
+ }
+ assertEquals(3 * FSEditLog.MIN_PREALLOCATION_LENGTH,
elfos.getFile().length());
+ } finally {
+ if (elfos != null) elfos.close();
+ if (TEST_EDITS.exists()) TEST_EDITS.delete();
+ }
+ }
/**
* Tests transaction logging in dfs.
