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https://issues.apache.org/jira/browse/HIVE-2201?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13068715#comment-13068715
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[email protected] commented on HIVE-2201:
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/952/
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(Updated 2011-07-20 23:31:54.007436)
Review request for hive, Yongqiang He, Ning Zhang, and namit jain.
Changes
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1. change block merge task too
2. change the capital file name
Summary
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reduce name node calls in hive by creating temporary directories
This addresses bug HIVE-2201.
https://issues.apache.org/jira/browse/HIVE-2201
Diffs (updated)
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trunk/ql/src/java/org/apache/hadoop/hive/ql/exec/ExecDriver.java 1148905
trunk/ql/src/java/org/apache/hadoop/hive/ql/exec/FileSinkOperator.java
1148905
trunk/ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java 1148905
trunk/ql/src/java/org/apache/hadoop/hive/ql/io/RCFileOutputFormat.java
1148905
trunk/ql/src/java/org/apache/hadoop/hive/ql/io/rcfile/merge/BlockMergeTask.java
1148905
trunk/ql/src/java/org/apache/hadoop/hive/ql/io/rcfile/merge/RCFileMergeMapper.java
1148905
Diff: https://reviews.apache.org/r/952/diff
Testing
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Thanks,
Siying
> reduce name node calls in hive by creating temporary directories
> ----------------------------------------------------------------
>
> Key: HIVE-2201
> URL: https://issues.apache.org/jira/browse/HIVE-2201
> Project: Hive
> Issue Type: Improvement
> Reporter: Namit Jain
> Assignee: Siying Dong
> Attachments: HIVE-2201.1.patch, HIVE-2201.2.patch, HIVE-2201.3.patch,
> HIVE-2201.4.patch
>
>
> Currently, in Hive, when a file gets written by a FileSinkOperator,
> the sequence of operations is as follows:
> 1. In tmp directory tmp1, create a tmp file _tmp_1
> 2. At the end of the operator, move
> /tmp1/_tmp_1 to /tmp1/1
> 3. Move directory /tmp1 to /tmp2
> 4. For all files in /tmp2, remove all files starting with _tmp and
> duplicate files.
> Due to speculative execution, a lot of temporary files are created
> in /tmp1 (or /tmp2). This leads to a lot of name node calls,
> specially for large queries.
> The protocol above can be modified slightly:
> 1. In tmp directory tmp1, create a tmp file _tmp_1
> 2. At the end of the operator, move
> /tmp1/_tmp_1 to /tmp2/1
> 3. Move directory /tmp2 to /tmp3
> 4. For all files in /tmp3, remove all duplicate files.
> This should reduce the number of tmp files.
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