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https://issues.apache.org/jira/browse/HDFS-17332?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17806170#comment-17806170
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Xing Lin commented on HDFS-17332:
---------------------------------
In this jira, we only addressed the above issue for DFSInputStream. We did not
work on DFSStripedInputStream for erasure coding read path. Erasure coding is
not used at Linkedin. If you need the same fix for DFSStripedInputStream,
please enhance DFSStripedInputStream#fetchBlockByteRange().
> DFSInputStream: avoid logging stacktrace until when we really need to fail a
> read request with a MissingBlockException
> ----------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-17332
> URL: https://issues.apache.org/jira/browse/HDFS-17332
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
> Reporter: Xing Lin
> Assignee: Xing Lin
> Priority: Minor
>
> In DFSInputStream#actualGetFromOneDataNode(), it would send the exception
> stacktrace to the dfsClient.LOG whenever we fail on a DN. However, in most
> cases, the read request will be served successfully by reading from the next
> available DN. The existence of exception stacktrace in the log has caused
> multiple hadoop users at Linkedin to consider this WARN message as the
> RC/fatal error for their jobs. We would like to improve the log message and
> avoid sending the stacktrace to dfsClient.LOG when a read succeeds. The
> stackTrace when reading reach DN is sent to the log only when we really need
> to fail a read request (when chooseDataNode()/refetchLocations() throws a
> BlockMissingException).
>
> Example stack trace
> {code:java}
> [12]<stderr>:23/11/30 23:01:33 WARN hdfs.DFSClient: Connection failure:
> Failed to connect to 10.150.91.13/10.150.91.13:71 for file
> /XXXX/part-yyyy-95b9909c-zzz-c000.avro for block
> BP-364971551-DatanodeIP-1448516588954:blk_zzzz_129864739321:java.net.SocketTimeoutException:
> 60000 millis timeout while waiting for channel to be ready for read. ch :
> java.nio.channels.SocketChannel[connected local=/ip:40492
> remote=datanodeIP:71] [12]<stderr>:java.net.SocketTimeoutException: 60000
> millis timeout while waiting for channel to be ready for read. ch :
> java.nio.channels.SocketChannel[connected local=/localIp:40492
> remote=datanodeIP:71] [12]<stderr>: at
> org.apache.hadoop.net.SocketIOWithTimeout.doIO(SocketIOWithTimeout.java:164)
> [12]<stderr>: at
> org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:161)
> [12]<stderr>: at
> org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:131)
> [12]<stderr>: at
> org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:118)
> [12]<stderr>: at java.io.FilterInputStream.read(FilterInputStream.java:83)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.protocolPB.PBHelperClient.vintPrefixed(PBHelperClient.java:458)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.client.impl.BlockReaderRemote2.newBlockReader(BlockReaderRemote2.java:412)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.client.impl.BlockReaderFactory.getRemoteBlockReader(BlockReaderFactory.java:864)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.client.impl.BlockReaderFactory.getRemoteBlockReaderFromTcp(BlockReaderFactory.java:753)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.client.impl.BlockReaderFactory.build(BlockReaderFactory.java:387)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.DFSInputStream.getBlockReader(DFSInputStream.java:736)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.DFSInputStream.actualGetFromOneDataNode(DFSInputStream.java:1268)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.DFSInputStream.fetchBlockByteRange(DFSInputStream.java:1216)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.DFSInputStream.pread(DFSInputStream.java:1608)
> [12]<stderr>: at
> org.apache.hadoop.hdfs.DFSInputStream.read(DFSInputStream.java:1568)
> [12]<stderr>: at
> org.apache.hadoop.fs.FSDataInputStream.read(FSDataInputStream.java:93)
> [12]<stderr>: at
> hdfs_metrics_shade.org.apache.hadoop.fs.InstrumentedFSDataInputStream$InstrumentedFilterInputStream.lambda$read$0(InstrumentedFSDataInputStream.java:108)
> [12]<stderr>: at
> com.linkedin.hadoop.metrics.fs.PerformanceTrackingFSDataInputStream.process(PerformanceTrackingFSDataInputStream.java:39)
> [12]<stderr>: at
> hdfs_metrics_shade.org.apache.hadoop.fs.InstrumentedFSDataInputStream$InstrumentedFilterInputStream.read(InstrumentedFSDataInputStream.java:108)
> [12]<stderr>: at
> org.apache.hadoop.fs.FSDataInputStream.read(FSDataInputStream.java:93)
> [12]<stderr>: at
> org.apache.hadoop.fs.RetryingInputStream.lambda$read$2(RetryingInputStream.java:153)
> [12]<stderr>: at
> org.apache.hadoop.fs.NoOpRetryPolicy.run(NoOpRetryPolicy.java:36)
> [12]<stderr>: at
> org.apache.hadoop.fs.RetryingInputStream.read(RetryingInputStream.java:149)
> [12]<stderr>: at
> org.apache.hadoop.fs.FSDataInputStream.read(FSDataInputStream.java:93){code}
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