[HDFS-10427] Write and Read SequenceFile Parallelly - java.io.IOException: Cannot obtain block length for LocatedBlock

• Type: Bug
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 2.7.2
• Component/s: datanode, namenode
• Assignee: Unassigned
• Reporter: Syed Akram
• Created: 18/May/16 15:58
• Updated: 11/Apr/19 14:41

Description

Trying to Write a key/value and Read already written key/value in a SequenceFile parallelly, But while doing that

Writer - appendOption true

java.io.IOException: Cannot obtain block length for LocatedBlock

{BP-1019538077-localhost-1459944245378:blk_1075356142_3219260; getBlockSize()=2409; corrupt=false; offset=0; locs=[DatanodeInfoWithStorage[dn1:50010,DS-21698924-4178-4c08-ba41-aa86770ef0d0,DISK], DatanodeInfoWithStorage[dn3:50010,DS-8e3dc8c0-4e34-4d12-86a3-48b189b78f5d,DISK], DatanodeInfoWithStorage[dn2:50010,DS-fb22c1c2-e059-4e0e-91e0-df838beb86f9,DISK]]}

at org.apache.hadoop.hdfs.DFSInputStream.readBlockLength(DFSInputStream.java:428)
at org.apache.hadoop.hdfs.DFSInputStream.fetchLocatedBlocksAndGetLastBlockLength(DFSInputStream.java:336)
at org.apache.hadoop.hdfs.DFSInputStream.openInfo(DFSInputStream.java:272)
at org.apache.hadoop.hdfs.DFSInputStream.<init>(DFSInputStream.java:264)
at org.apache.hadoop.hdfs.DFSClient.open(DFSClient.java:1526)
at org.apache.hadoop.hdfs.DistributedFileSystem$3.doCall(DistributedFileSystem.java:303)
at org.apache.hadoop.hdfs.DistributedFileSystem$3.doCall(DistributedFileSystem.java:299)
at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
at org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSystem.java:299)
at org.apache.hadoop.io.SequenceFile$Reader.openFile(SequenceFile.java:1902)
at org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1822)

But when i'm trying to read when write (SequenceFile.Writer )is opened, it works fine,

But when we do parallelly (both start write with append=true and then read already existing key/value) then facing this issue.