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https://issues.apache.org/jira/browse/HIVE-1326?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12861467#action_12861467
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Ning Zhang commented on HIVE-1326:
----------------------------------
Michael, the temporary directory is needed for a conditional task to handle
skewed joins (that's why the JobConf is cloned but with a different path). The
idea here is that whenever there many too many rows for a particular job key to
be held in memory, they will be first write to local disk via RowContainer. If
there are still too many rows to local disk, they will be write to a DFS
location and a contitional task will be triggered to handle this skewed key. So
if we create a temp directory in local disk and let all mappers write their
temp files in that directory, then later when we want to move the data to HDFS,
we just move the whole directory instead of moving individual files.
+1 on v2. Will commit if tests pass.
> RowContainer uses hard-coded '/tmp/' path for temporary files
> -------------------------------------------------------------
>
> Key: HIVE-1326
> URL: https://issues.apache.org/jira/browse/HIVE-1326
> Project: Hadoop Hive
> Issue Type: Bug
> Environment: Hadoop 0.19.2 with Hive trunk. We're using FreeBSD 7.0,
> but that doesn't seem relevant.
> Reporter: Michael Klatt
> Attachments: rowcontainer.patch, rowcontainer_v2.patch
>
>
> In our production hadoop environment, the "/tmp/" is actually pretty small,
> and we encountered a problem when a query used the RowContainer class and
> filled up the /tmp/ partition. I tracked down the cause to the RowContainer
> class putting temporary files in the '/tmp/' path instead of using the
> configured Hadoop temporary path. I've attached a patch to fix this.
> Here's the traceback:
> 2010-04-25 12:05:05,120 INFO
> org.apache.hadoop.hive.ql.exec.persistence.RowContainer: RowContainer created
> temp file /tmp/hive-rowcontainer-1244151903/RowContainer7816.tmp
> 2010-04-25 12:05:06,326 INFO ExecReducer: ExecReducer: processing 10000000
> rows: used memory = 385520312
> 2010-04-25 12:05:08,513 INFO ExecReducer: ExecReducer: processing 11000000
> rows: used memory = 341780472
> 2010-04-25 12:05:10,697 INFO ExecReducer: ExecReducer: processing 12000000
> rows: used memory = 301446768
> 2010-04-25 12:05:12,837 INFO ExecReducer: ExecReducer: processing 13000000
> rows: used memory = 399208768
> 2010-04-25 12:05:15,085 INFO ExecReducer: ExecReducer: processing 14000000
> rows: used memory = 364507216
> 2010-04-25 12:05:17,260 INFO ExecReducer: ExecReducer: processing 15000000
> rows: used memory = 332907280
> 2010-04-25 12:05:19,580 INFO ExecReducer: ExecReducer: processing 16000000
> rows: used memory = 298774096
> 2010-04-25 12:05:21,629 INFO ExecReducer: ExecReducer: processing 17000000
> rows: used memory = 396505408
> 2010-04-25 12:05:23,830 INFO ExecReducer: ExecReducer: processing 18000000
> rows: used memory = 362477288
> 2010-04-25 12:05:25,914 INFO ExecReducer: ExecReducer: processing 19000000
> rows: used memory = 327229744
> 2010-04-25 12:05:27,978 INFO ExecReducer: ExecReducer: processing 20000000
> rows: used memory = 296051904
> 2010-04-25 12:05:28,155 FATAL ExecReducer: org.apache.hadoop.fs.FSError:
> java.io.IOException: No space left on device
> at
> org.apache.hadoop.fs.RawLocalFileSystem$LocalFSFileOutputStream.write(RawLocalFileSystem.java:199)
> at
> java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
> at java.io.BufferedOutputStream.write(BufferedOutputStream.java:109)
> at
> org.apache.hadoop.fs.FSDataOutputStream$PositionCache.write(FSDataOutputStream.java:49)
> at java.io.DataOutputStream.write(DataOutputStream.java:90)
> at
> org.apache.hadoop.fs.ChecksumFileSystem$ChecksumFSOutputSummer.writeChunk(ChecksumFileSystem.java:346)
> at
> org.apache.hadoop.fs.FSOutputSummer.writeChecksumChunk(FSOutputSummer.java:150)
> at
> org.apache.hadoop.fs.FSOutputSummer.flushBuffer(FSOutputSummer.java:132)
> at
> org.apache.hadoop.fs.FSOutputSummer.flushBuffer(FSOutputSummer.java:121)
> at org.apache.hadoop.fs.FSOutputSummer.write1(FSOutputSummer.java:112)
> at org.apache.hadoop.fs.FSOutputSummer.write(FSOutputSummer.java:86)
> at
> org.apache.hadoop.fs.FSDataOutputStream$PositionCache.write(FSDataOutputStream.java:49)
> at java.io.DataOutputStream.write(DataOutputStream.java:90)
> at
> org.apache.hadoop.io.SequenceFile$Writer.append(SequenceFile.java:1013)
> at
> org.apache.hadoop.io.SequenceFile$Writer.append(SequenceFile.java:977)
> at
> org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat$1.write(HiveSequenceFileOutputFormat.java:70)
> at
> org.apache.hadoop.hive.ql.exec.persistence.RowContainer.spillBlock(RowContainer.java:343)
> at
> org.apache.hadoop.hive.ql.exec.persistence.RowContainer.add(RowContainer.java:163)
> at
> org.apache.hadoop.hive.ql.exec.JoinOperator.processOp(JoinOperator.java:118)
> at org.apache.hadoop.hive.ql.exec.Operator.process(Operator.java:456)
> at
> org.apache.hadoop.hive.ql.exec.ExecReducer.reduce(ExecReducer.java:244)
> at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:436)
> at org.apache.hadoop.mapred.Child.main(Child.java:158)
> Caused by: java.io.IOException: No space left on device
> at java.io.FileOutputStream.writeBytes(Native Method)
> at java.io.FileOutputStream.write(FileOutputStream.java:260)
> at
> org.apache.hadoop.fs.RawLocalFileSystem$LocalFSFileOutputStream.write(RawLocalFileSystem.java:197)
> ... 22 more
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