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From "Aman Sinha (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DRILL-3735) Directory pruning is not happening when number of files is larger than 64k
Date Mon, 14 Sep 2015 18:41:45 GMT

    [ https://issues.apache.org/jira/browse/DRILL-3735?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14743999#comment-14743999

Aman Sinha commented on DRILL-3735:

[~mehant] could you pls review ? 

> Directory pruning is not happening when number of files is larger than 64k
> --------------------------------------------------------------------------
>                 Key: DRILL-3735
>                 URL: https://issues.apache.org/jira/browse/DRILL-3735
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Query Planning & Optimization
>    Affects Versions: 1.1.0
>            Reporter: Hao Zhu
>            Assignee: Mehant Baid
>             Fix For: 1.2.0
> When the number of files is larger than 64k limit, directory pruning is not happening.

> We need to increase this limit further to handle most use cases.
> My proposal is to separate the code for directory pruning and partition pruning. 
> Say in a parent directory there are 100 directories and 1 million files.
> If we only query the file from one directory, we should firstly read the 100 directories
and narrow down to which directory; and then read the file paths in that directory in memory
and do the rest stuff.
> Current behavior is , Drill will read all the file paths of that 1 million files in memory
firstly, and then do directory pruning or partition pruning. This is not performance efficient
nor memory efficient. And also it can not scale.

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