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From "Owen O'Malley" <owen.omal...@gmail.com>
Subject Re: SearchArguments column names and nested columns
Date Wed, 06 Dec 2017 18:37:41 GMT
On Tue, Dec 5, 2017 at 6:17 AM, Emilio Lahr-Vivaz <elahrvivaz@ccri.com>
wrote:

> Hello,
>
> I have two questions related to SearchArguments and predicate push down
> that I couldn't find documented anywhere.
>
> 1. What is the 'columnNames' parameter used for in the searchArgument [1]
> method? In my testing, it doesn't seem to make a difference if I pass in
> the column I'm filtering, some other column, or even an empty array.
>

You're right. It isn't used any more, and should be documented as such. It
used to be important when the column names weren't passed down to ORC from
Hive. I've created ORC-274.


> 2. Is it possible to create a predicate on a nested column? From tracing
> through the code it doesn't appear to be possible, but wanted to confirm.
> For example, I'd like to filter on location.x given a type description
> like: struct<id:string,location:struct<x:double,y:double>>
>

It currently isn't, but it be nice if someone wants to work on it. I've
created ORC-275 for that.

.. Owen


>
> Thanks,
>
> Emilio
>
> [1]: https://orc.apache.org/api/orc-core/org/apache/orc/Reader.
> Options.html#searchArgument-org.apache.hadoop.hive.ql.io.
> sarg.SearchArgument-java.lang.String:A-
>

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