[HDFS-16896] HDFS Client hedged read has increased failure rate than without hedged read

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.0, 3.3.5
• Fix Version/s: 3.4.0, 3.3.5
• Component/s: hdfs-client
• Labels: pull-request-available
• Target Version/s: 3.4.0, 3.3.5
• Hadoop Flags: Reviewed
• Assignee: Tom McCormick
• Reporter: Tom McCormick
• Created: 24/Jan/23 07:30
• Updated: 28/Jan/24 07:24
• Resolved: 02/Mar/23 00:52

Description

When hedged read is enabled by HDFS client, we see an increased failure rate on reads.

stacktrace

 

Caused by: org.apache.hadoop.hdfs.BlockMissingException: Could not obtain block: BP-1183972111-10.197.192.88-1590025572374:blk_17114848218_16043459722 file=/data/tracking/streaming/AdImpressionEvent/daily/2022/07/18/compaction_1/part-r-1914862.1658217125623.1362294472.orc
at org.apache.hadoop.hdfs.DFSInputStream.refetchLocations(DFSInputStream.java:1077)
at org.apache.hadoop.hdfs.DFSInputStream.chooseDataNode(DFSInputStream.java:1060)
at org.apache.hadoop.hdfs.DFSInputStream.chooseDataNode(DFSInputStream.java:1039)
at org.apache.hadoop.hdfs.DFSInputStream.hedgedFetchBlockByteRange(DFSInputStream.java:1365)
at org.apache.hadoop.hdfs.DFSInputStream.pread(DFSInputStream.java:1572)
at org.apache.hadoop.hdfs.DFSInputStream.read(DFSInputStream.java:1535)
at org.apache.hadoop.fs.FSInputStream.readFully(FSInputStream.java:121)
at org.apache.hadoop.fs.FSDataInputStream.readFully(FSDataInputStream.java:112)
at org.apache.hadoop.fs.RetryingInputStream.lambda$readFully$3(RetryingInputStream.java:172)
at org.apache.hadoop.fs.RetryPolicy.lambda$run$0(RetryPolicy.java:137)
at org.apache.hadoop.fs.NoOpRetryPolicy.run(NoOpRetryPolicy.java:36)
at org.apache.hadoop.fs.RetryPolicy.run(RetryPolicy.java:136)
at org.apache.hadoop.fs.RetryingInputStream.readFully(RetryingInputStream.java:168)
at org.apache.hadoop.fs.FSDataInputStream.readFully(FSDataInputStream.java:112)
at org.apache.hadoop.fs.FSDataInputStream.readFully(FSDataInputStream.java:112)
at io.trino.plugin.hive.orc.HdfsOrcDataSource.readInternal(HdfsOrcDataSource.java:76)
... 46 more

 

Issue Links

• links to: GitHub Pull Request #5322
• links to: GitHub Pull Request #5444