[jira] [Assigned] (SPARK-18457) ORC and other columnar formats using HiveShim read all columns when doing a simple count

["Apache Spark (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-18457?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Apache Spark reassigned SPARK-18457:
------------------------------------

    Assignee:     (was: Apache Spark)

> ORC and other columnar formats using HiveShim read all columns when doing a simple count
> ----------------------------------------------------------------------------------------
>
>                 Key: SPARK-18457
>                 URL: https://issues.apache.org/jira/browse/SPARK-18457
>             Project: Spark
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 1.6.3, 2.0.2
>         Environment: Hadoop 2.7.0
>            Reporter: Andrew Ray
>            Priority: Minor
>
> Doing a `select count(*) from a_orc_table` reads all columns and thus is slower than a query selecting one like `select count(a_column) from a_orc_table`. Data read can be seen in the UI (appears to only be accurate for Hadoop 2.5+ based on comment in FileScanRDD.scala line 80).
> I will create a PR shortly.



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