Uma Maheswara Rao G created HBASE-5878:
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Summary: Use getVisibleLength public api from HdfsDataInputStream
from Hadoop-2.
Key: HBASE-5878
URL: https://issues.apache.org/jira/browse/HBASE-5878
Project: HBase
Issue Type: Bug
Components: wal
Reporter: Uma Maheswara Rao G
Assignee: Uma Maheswara Rao G
SequencFileLogReader:
Currently Hbase using getFileLength api from DFSInputStream class by
reflection. DFSInputStream is not exposed as public. So, this may change in
future. Now HDFS exposed HdfsDataInputStream as public API.
We can make use of it, when we are not able to find the getFileLength api from
DFSInputStream as a else condition. So, that we will not have any sudden
surprise like we are facing today.
Also, it is just logging one warn message and proceeding if it throws any
exception while getting the length. I think we can re-throw the exception
because there is no point in continuing with dataloss.
{code}
long adjust = 0;
try {
Field fIn = FilterInputStream.class.getDeclaredField("in");
fIn.setAccessible(true);
Object realIn = fIn.get(this.in);
// In hadoop 0.22, DFSInputStream is a standalone class. Before
this,
// it was an inner class of DFSClient.
if (realIn.getClass().getName().endsWith("DFSInputStream")) {
Method getFileLength = realIn.getClass().
getDeclaredMethod("getFileLength", new Class<?> []{});
getFileLength.setAccessible(true);
long realLength = ((Long)getFileLength.
invoke(realIn, new Object []{})).longValue();
assert(realLength >= this.length);
adjust = realLength - this.length;
} else {
LOG.info("Input stream class: " + realIn.getClass().getName() +
", not adjusting 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();
{code}
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