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https://issues.apache.org/jira/browse/HIVE-2201?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13054508#comment-13054508
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He Yongqiang commented on HIVE-2201:
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1. why do you need to change "RCFileOutputFormat"
2. have you tested this code?
3. in Utilities, why tmpPath is still there together with taskTmpPath? And 2
toTaskTempPath(), keep one
4. CreateTmpDirs, lower case, and CreateTmpDirs use 2 loop, use values(). why
is this even needed?
5. I think not just FileSinkOperator have this logic, you should change them all
> 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
>
>
> 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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