ZhangBiao created HDFS-12326:
--------------------------------

             Summary: What is the correct way of retrying when failure occurs 
during writing
                 Key: HDFS-12326
                 URL: https://issues.apache.org/jira/browse/HDFS-12326
             Project: Hadoop HDFS
          Issue Type: Test
          Components: hdfs-client
            Reporter: ZhangBiao


I'm using hdfs client for golang https://github.com/colinmarc/hdfs to write to 
the hdfs.
When the number of files concurrently being opened is larger, for example 200. 
I'll always get the 'broken pipe' error.

So I want to retry to continue writing. What is the correct way of retrying? 
Because https://github.com/colinmarc/hdfs hasn't been able to recover the 
stream status when an error occurs duing writing, so I have to reopen and get a 
new stream. So I tried the following steps:
1 close the current stream
2 Append the file to get a new stream

But when I close the stream, I got the error "updateBlockForPipeline call 
failed with ERROR_APPLICATION (java.io.IOException"
and it seems the namenode complains:

{code:java}
2017-08-20 03:22:55,598 INFO org.apache.hadoop.ipc.Server: IPC Server handler 2 
on 9000, call 
org.apache.hadoop.hdfs.protocol.ClientProtocol.updateBlockForPipeline from 
192.168.0.39:46827 Call#50183 Retry#-1
java.io.IOException: 
BP-1152809458-192.168.0.39-1502261411064:blk_1073825071_111401 does not exist 
or is not under Constructionblk_1073825071_111401{UCState=COMMITTED, 
truncateBlock=null, primaryNodeIndex=-1, 
replicas=[ReplicaUC[[DISK]DS-d61914ba-df64-467b-bb75-272875e5e865:NORMAL:192.168.0.39:50010|RBW],
 
ReplicaUC[[DISK]DS-1314debe-ab08-4001-ab9a-8e234f28f87c:NORMAL:192.168.0.38:50010|RBW]]}
    at 
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkUCBlock(FSNamesystem.java:6241)
    at 
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.updateBlockForPipeline(FSNamesystem.java:6309)
    at 
org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.updateBlockForPipeline(NameNodeRpcServer.java:806)
    at 
org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.updateBlockForPipeline(ClientNamenodeProtocolServerSideTranslatorPB.java:955)
    at 
org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
    at 
org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:982)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at 
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1698)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)
2017-08-20 03:22:56,333 INFO 
org.apache.hadoop.hdfs.server.namenode.FSNamesystem: BLOCK* 
blk_1073825071_111401{UCState=COMMITTED, truncateBlock=null, 
primaryNodeIndex=-1, 
replicas=[ReplicaUC[[DISK]DS-d61914ba-df64-467b-bb75-272875e5e865:NORMAL:192.168.0.39:50010|RBW],
 
ReplicaUC[[DISK]DS-1314debe-ab08-4001-ab9a-8e234f28f87c:NORMAL:192.168.0.38:50010|RBW]]}
 is not COMPLETE (ucState = COMMITTED, replication# = 0 <  minimum = 1) in file 
/user/am/scan_task/2017-08-20/192.168.0.38_audience_f/user-bak010-20170820030804.log
{code}

when I Appended to get a new stream, I got the error 'append call failed with 
ERROR_APPLICATION 
(org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException)', and the 
corresponding error in namenode is:

{code:java}
2017-08-20 03:22:56,335 WARN org.apache.hadoop.hdfs.StateChange: DIR* 
NameSystem.append: Failed to APPEND_FILE 
/user/am/scan_task/2017-08-20/192.168.0.38_audience_f/user-bak010-20170820030804.log
 for go-hdfs-OAfvZiSUM2Eu894p on 192.168.0.39 because go-hdfs-OAfvZiSUM2Eu894p 
is already the current lease holder.
2017-08-20 03:22:56,335 INFO org.apache.hadoop.ipc.Server: IPC Server handler 0 
on 9000, call org.apache.hadoop.hdfs.protocol.ClientProtocol.append from 
192.168.0.39:46827 Call#50186 Retry#-1: 
org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException: Failed to 
APPEND_FILE 
/user/am/scan_task/2017-08-20/192.168.0.38_audience_f/user-bak010-20170820030804.log
 for go-hdfs-OAfvZiSUM2Eu894p on 192.168.0.39 because go-hdfs-OAfvZiSUM2Eu894p 
is already the current lease holder.
{code}

Could you please suggest the correct way of retrying of the client side when 
write fails?



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