[jira] [Updated] (HIVE-24021) Read insert-only tables truncated by Impala correctly

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-24021?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ASF GitHub Bot updated HIVE-24021:
----------------------------------
    Labels: pull-request-available  (was: )

> Read insert-only tables truncated by Impala correctly
> -----------------------------------------------------
>
>                 Key: HIVE-24021
>                 URL: https://issues.apache.org/jira/browse/HIVE-24021
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Karen Coppage
>            Assignee: Karen Coppage
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> Impala truncates insert-only tables by writing a base directory containing an empty file named "_empty". (Like Hive should, see HIVE-20137) Generally in Hive a file name beginning with an underscore connotes a temporary file that isn't supposed to be read by operations that didn't create it.
>  Before HIVE-23495, getAcidState listed each directory in the table (HdfsUtils#listLocatedStatus) – and filtered out directories with names beginning with an underscore or period as they are presumably temporary. This allowed files called "_empty" to be read, since hive checked the directory name and not the file name.
>  After HIVE-23495, we recursively list each file in the table (AcidUtils#getHdfsDirSnapshots) with a filter that doesn't accept files with names beginning with an underscore or period as they are presumably temporary. As a result Hive reads the table data as if the truncate operation had not happened.
> Since performance in getAcidState is important, probably the best solution is make an exception in the filter and accept files with the name "_empty".



--
This message was sent by Atlassian Jira
(v8.3.4#803005)