Author: stack
Date: Tue Sep 28 05:29:29 2010
New Revision: 1002020
URL: http://svn.apache.org/viewvc?rev=1002020&view=rev
Log:
HBASE-2646 Compaction requests should be prioritized to prevent blocking;
remove of hbase-3038 added by mistake
Modified:
hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/wal/SequenceFileLogReader.java
Modified:
hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/wal/SequenceFileLogReader.java
URL:
http://svn.apache.org/viewvc/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/wal/SequenceFileLogReader.java?rev=1002020&r1=1002019&r2=1002020&view=diff
==============================================================================
---
hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/wal/SequenceFileLogReader.java
(original)
+++
hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/wal/SequenceFileLogReader.java
Tue Sep 28 05:29:29 2010
@@ -20,7 +20,7 @@
package org.apache.hadoop.hbase.regionserver.wal;
-import java.io.FilterInputStream;
+import java.io.EOFException;
import java.io.IOException;
import java.lang.Class;
import java.lang.reflect.Constructor;
@@ -78,43 +78,18 @@ public class SequenceFileLogReader imple
this.length = l;
}
- // This section can be confusing. It is specific to how HDFS works.
- // Let me try to break it down. This is the problem:
- //
- // 1. HDFS DataNodes update the NameNode about a filename's length
- // on block boundaries or when a file is closed. Therefore,
- // if an RS dies, then the NN's fs.getLength() can be out of date
- // 2. this.in.available() would work, but it returns int &
- // therefore breaks for files > 2GB (happens on big clusters)
- // 3. DFSInputStream.getFileLength() gets the actual length from the DNs
- // 4. DFSInputStream is wrapped 2 levels deep : this.in.in
- //
- // So, here we adjust getPos() using getFileLength() so the
- // SequenceFile.Reader constructor (aka: first invocation) comes out
- // with the correct end of the file:
- // this.end = in.getPos() + length;
@Override
public long getPos() throws IOException {
if (this.firstGetPosInvocation) {
this.firstGetPosInvocation = false;
- long adjust = 0;
-
- try {
- Field fIn = FilterInputStream.class.getDeclaredField("in");
- fIn.setAccessible(true);
- Object realIn = fIn.get(this.in);
- long realLength = ((Long)realIn.getClass().
- getMethod("getFileLength", new Class<?> []{}).
- invoke(realIn, new Object []{})).longValue();
- assert(realLength >= this.length);
- adjust = realLength - this.length;
- } catch(Exception e) {
- SequenceFileLogReader.LOG.warn(
- "Error while trying to get accurate file length. " +
- "Truncation / data loss may occur if RegionServers die.", e);
- }
-
- return adjust + super.getPos();
+ // Tell a lie. We're doing this just so that this line up in
+ // SequenceFile.Reader constructor comes out with the correct length
+ // on the file:
+ // this.end = in.getPos() + length;
+ long available = this.in.available();
+ // Length gets added up in the SF.Reader constructor so subtract the
+ // difference. If available < this.length, then return this.length.
+ return available >= this.length? available - this.length:
this.length;
}
return super.getPos();
}
