[jira] [Resolved] (IMPALA-6899) Dataload uses excessive HDFS commands

["Joe McDonnell (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-6899?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Joe McDonnell resolved IMPALA-6899.
-----------------------------------
       Resolution: Fixed
    Fix Version/s: Impala 2.13.0
                   Impala 3.0

> Dataload uses excessive HDFS commands
> -------------------------------------
>
>                 Key: IMPALA-6899
>                 URL: https://issues.apache.org/jira/browse/IMPALA-6899
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Infrastructure
>    Affects Versions: Impala 3.1.0
>            Reporter: Joe McDonnell
>            Assignee: Joe McDonnell
>            Priority: Major
>             Fix For: Impala 3.0, Impala 2.13.0
>
>
> Dataload has several locations where it does a long string of HDFS commands similar to this:
>  
> {code:java}
> hdfs dfs -mkdir bad_table1
> hdfs dfs -put bad_file_1 bad_table1
> hdfs dfs -put bad_file_2 bad_table1
> hdfs dfs -mkdir bad_table2
> hdfs dfs -put bad_file_3 bad_table2
> hdfs dfs -put bad_file_4 bad_table2{code}
> Most hdfs shell commands can take multiple arguments. In particular, "mkdir" can make multiple directories in one command. "put" can copy multiple files into a single destination. This can save on hdfs commandline invocations, which are often expensive due to JVM startup and other costs. For example, the above is equivalent to:
>  
> {code:java}
> hdfs dfs -mkdir bad_table1 bad_table2
> hdfs dfs -put bad_file_1 bad_file_2 bad_table1
> hdfs dfs -put bad_file_3 bad_file_4 bad_table2{code}
> Dataload should make these types of optimizations wherever possible.
>  
>  



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