Binglin Chang created HDFS-4272:
-----------------------------------
Summary: Problem in DFSInputStream read retry logic may cause
early failure
Key: HDFS-4272
URL: https://issues.apache.org/jira/browse/HDFS-4272
Project: Hadoop HDFS
Issue Type: Bug
Reporter: Binglin Chang
Assignee: Binglin Chang
Priority: Minor
Assume the following call logic
{noformat}
readWithStrategy()
-> blockSeekTo()
-> readBuffer()
-> reader.doRead()
-> seekToNewSource() add currentNode to deadnode, wish to get a different
datanode
-> blockSeekTo()
-> chooseDataNode()
-> block missing, clear deadNodes and pick the currentNode again
seekToNewSource() return false
readBuffer() re-throw the exception quit loop
readWithStrategy() got the exception, and may fail the read call before tried
MaxBlockAcquireFailures.
{noformat}
some issues of the logic:
1. seekToNewSource() logic is broken because it may clear deadNodes in the
middle.
2. the variable "int retries=2" in readWithStrategy seems have conflict with
MaxBlockAcquireFailures, should it be removed?
I write a test to produce the scenario, and here is part of the log:
{noformat}
2012-12-05 22:55:15,135 WARN hdfs.DFSClient
(DFSInputStream.java:readBuffer(596)) - Found Checksum error for
BP-50712310-192.168.0.101-1354719313473:blk_-705068286766485620_1002 from
127.0.0.1:50099 at 0
2012-12-05 22:55:15,136 INFO DataNode.clienttrace
(BlockSender.java:sendBlock(672)) - src: /127.0.0.1:50099, dest:
/127.0.0.1:50105, bytes: 4128, op: HDFS_READ, cliID:
DFSClient_NONMAPREDUCE_-1488457569_1, offset: 0, srvID:
DS-91625336-192.168.0.101-50099-1354719314603, blockid:
BP-50712310-192.168.0.101-1354719313473:blk_-705068286766485620_1002, duration:
2925000
2012-12-05 22:55:15,136 INFO hdfs.DFSClient
(DFSInputStream.java:chooseDataNode(741)) - Could not obtain
BP-50712310-192.168.0.101-1354719313473:blk_-705068286766485620_1002 from any
node: java.io.IOException: No live nodes contain current block. Will get new
block locations from namenode and retry...
2012-12-05 22:55:15,136 WARN hdfs.DFSClient
(DFSInputStream.java:chooseDataNode(756)) - DFS chooseDataNode: got # 1
IOException, will wait for 274.34891931868265 msec.
2012-12-05 22:55:15,413 INFO DataNode.clienttrace
(BlockSender.java:sendBlock(672)) - src: /127.0.0.1:50099, dest:
/127.0.0.1:50106, bytes: 4128, op: HDFS_READ, cliID:
DFSClient_NONMAPREDUCE_-1488457569_1, offset: 0, srvID:
DS-91625336-192.168.0.101-50099-1354719314603, blockid:
BP-50712310-192.168.0.101-1354719313473:blk_-705068286766485620_1002, duration:
283000
2012-12-05 22:55:15,414 INFO hdfs.StateChange
(FSNamesystem.java:reportBadBlocks(4761)) - *DIR* reportBadBlocks
2012-12-05 22:55:15,415 INFO BlockStateChange
(CorruptReplicasMap.java:addToCorruptReplicasMap(66)) - BLOCK
NameSystem.addToCorruptReplicasMap: blk_-705068286766485620 added as corrupt on
127.0.0.1:50099 by null because client machine reported it
2012-12-05 22:55:15,416 INFO hdfs.TestClientReportBadBlock
(TestDFSInputStream.java:testDFSInputStreamReadRetryTime(94)) - catch
IOExceptionorg.apache.hadoop.fs.ChecksumException: Checksum error: /testFile at
0 exp: 809972010 got: -1374622118
2012-12-05 22:55:15,431 INFO hdfs.MiniDFSCluster
(MiniDFSCluster.java:shutdown(1411)) - Shutting down the Mini HDFS Cluster
{noformat}
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
