[jira] [Commented] (HIVE-14864) Distcp is not called from MoveTask when src is a directory

["Mohit Sabharwal (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-14864?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15536842#comment-15536842 ] 

Mohit Sabharwal commented on HIVE-14864:
----------------------------------------

Does srcFS.getContentSummary(src).getLength() return total number of files in the directory ? 

I think this whole condition needs to be re-thought. Because AFAIK, DistCp speeds up copies when multiple
files are involved. There is no advantage in DistCp'ing a single file, no matter how big that file. Which means
HIVE_EXEC_COPYFILE_MAXSIZE does not make sense even for a file.

IOW, we need to look into DistCp'ing directories only, and possibly ones which contain more than a threshold
number of files.

> Distcp is not called from MoveTask when src is a directory
> ----------------------------------------------------------
>
>                 Key: HIVE-14864
>                 URL: https://issues.apache.org/jira/browse/HIVE-14864
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Vihang Karajgaonkar
>            Assignee: Vihang Karajgaonkar
>
> In FileUtils.java the following code does not get executed even when src directory size is greater than HIVE_EXEC_COPYFILE_MAXSIZE because 
> srcFS.getFileStatus(src).getLen() returns 0 when src is a directory. We should use srcFS.getContentSummary(src).getLength() instead.
> {noformat}
>     /* Run distcp if source file/dir is too big */
>     if (srcFS.getUri().getScheme().equals("hdfs") &&
>         srcFS.getFileStatus(src).getLen() > conf.getLongVar(HiveConf.ConfVars.HIVE_EXEC_COPYFILE_MAXSIZE)) {
>       LOG.info("Source is " + srcFS.getFileStatus(src).getLen() + " bytes. (MAX: " + conf.getLongVar(HiveConf.ConfVars.HIVE_EXEC_COPYFILE_MAXSIZE) + ")");
>       LOG.info("Launch distributed copy (distcp) job.");
>       HiveConfUtil.updateJobCredentialProviders(conf);
>       copied = shims.runDistCp(src, dst, conf);
>       if (copied && deleteSource) {
>         srcFS.delete(src, true);
>       }
>     }
> {noformat}



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