Lucas Pauchard created NUTCH-2756:
-------------------------------------
Summary: Segment Part problem with HDFS on distibuted mode
Key: NUTCH-2756
URL: https://issues.apache.org/jira/browse/NUTCH-2756
Project: Nutch
Issue Type: Bug
Components: parser
Affects Versions: 1.15
Reporter: Lucas Pauchard
Attachments: 0_byte_file_screenshot.PNG
During the parsing, it happens sometimes that parts of the data on the HDFS is
missing after the parsing.
When I take a look at our HDFS, I've got this file with 0 bytes (see
attachments).
After that the CrawlDB complains about this specific (corrupted?) part:
~2019-12-04 22:25:57,454 INFO mapreduce.Job: Task Id :
attempt_1575479127636_0047_m_000017_2, Status : FAILED
Error: java.io.EOFException:
hdfs://jobmaster:9000/user/hadoop/crawlmultiokhttp/segment/20191204221308/crawl_parse/part-r-00004
not a SequenceFile
at org.apache.hadoop.io.SequenceFile$Reader.init(SequenceFile.java:1964)
at
org.apache.hadoop.io.SequenceFile$Reader.initialize(SequenceFile.java:1923)
at
org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1872)
at
org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1886)
at
org.apache.hadoop.mapreduce.lib.input.SequenceFileRecordReader.initialize(SequenceFileRecordReader.java:54)
at
org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.initialize(MapTask.java:560)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:798)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:347)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:174)
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:1729)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:168)~
When I check the namenode logs, I don't see any error during the writing of the
segment part but one hour later, I've got the following log:
~2019-12-04 23:23:13,750 INFO
org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Recovering [Lease.
Holder: DFSClient_attempt_1575479127636_0046_r_000004_1_1307945884_1, pending
creates: 2],
src=/user/hadoop/crawlmultiokhttp/segment/20191204221308/parse_data/part-r-00004/index
2019-12-04 23:23:13,750 WARN org.apache.hadoop.hdfs.StateChange: BLOCK*
internalReleaseLease: All existing blocks are COMPLETE, lease removed, file
/user/hadoop/crawlmultiokhttp/segment/20191204221308/parse_data/part-r-00004/index
closed.
2019-12-04 23:23:13,750 INFO
org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Recovering [Lease.
Holder: DFSClient_attempt_1575479127636_0046_r_000004_1_1307945884_1, pending
creates: 1],
src=/user/hadoop/crawlmultiokhttp/segment/20191204221308/crawl_parse/part-r-00004
2019-12-04 23:23:13,750 WARN org.apache.hadoop.hdfs.StateChange: BLOCK*
internalReleaseLease: All existing blocks are COMPLETE, lease removed, file
/user/hadoop/crawlmultiokhttp/segment/20191204221308/crawl_parse/part-r-00004
closed.
~
This issue is hard to reproduce and I can't figure out what are the
preconditions. It seems that it just happens randomly.
Maybe the problem is coming from a bad management when we close the file.
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