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Posted to user@hive.apache.org by Xiaoyong Zhu <xi...@microsoft.com> on 2015/03/27 14:42:11 UTC
Sort order in Hive plan?
Hi experts
When I am viewing the Hive plans, I notice that in Reduce Output Operators, there is a "property" named "sort order" and it's value is "+++" - may I know what's the meaning of the three plus signs? Sometime I also see one plus sign...
Is there any document talking about this? Or where could I refer to the code?
[cid:image003.jpg@01D068D6.DF717870]
Thanks!
Xiaoyong
Re: Sort order in Hive plan?
Posted by Lefty Leverenz <le...@gmail.com>.
Thanks Xiaoyong Zhu and Prasanth Jayachandran, I've added this information
to the wiki in EXPLAIN Syntax
<https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=27362037#LanguageManualExplain-EXPLAINSyntax>
after
the example stage plans.
-- Lefty
On Fri, Mar 27, 2015 at 8:07 PM, Xiaoyong Zhu <xi...@microsoft.com>
wrote:
> Thanks for the clarification!
>
>
>
> Xiaoyong
>
>
>
> *From:* Prasanth Jayachandran [mailto:pjayachandran@hortonworks.com]
> *Sent:* Saturday, March 28, 2015 1:02 AM
> *To:* user@hive.apache.org; user@hive.apache.org
> *Subject:* Re: Sort order in Hive plan?
>
>
>
> Hi
>
>
>
> In the image that you had posted. There are 4 plus signs which means
> sorting happens on all four columns in key expression. Number of plus signs
> indicate the number of columns in key expressions that are used for
> sorting. Also minus sign indicate that sorting happens in descending order.
>
>
> Thanks
> Prasanth
>
>
>
>
>
> On Fri, Mar 27, 2015 at 6:43 AM -0700, "Xiaoyong Zhu" <
> xiaoyzhu@microsoft.com> wrote:
>
> Hi experts
>
>
>
> When I am viewing the Hive plans, I notice that in Reduce Output
> Operators, there is a “property” named “sort order” and it’s value is “+++”
> – may I know what’s the meaning of the three plus signs? Sometime I also
> see one plus sign…
>
> Is there any document talking about this? Or where could I refer to the
> code?
>
>
>
> Thanks!
>
>
>
> Xiaoyong
>
>
>
RE: Sort order in Hive plan?
Posted by Xiaoyong Zhu <xi...@microsoft.com>.
Thanks for the clarification!
Xiaoyong
From: Prasanth Jayachandran [mailto:pjayachandran@hortonworks.com]
Sent: Saturday, March 28, 2015 1:02 AM
To: user@hive.apache.org; user@hive.apache.org
Subject: Re: Sort order in Hive plan?
Hi
In the image that you had posted. There are 4 plus signs which means sorting happens on all four columns in key expression. Number of plus signs indicate the number of columns in key expressions that are used for sorting. Also minus sign indicate that sorting happens in descending order.
Thanks
Prasanth
On Fri, Mar 27, 2015 at 6:43 AM -0700, "Xiaoyong Zhu" <xi...@microsoft.com>> wrote:
Hi experts
When I am viewing the Hive plans, I notice that in Reduce Output Operators, there is a "property" named "sort order" and it's value is "+++" - may I know what's the meaning of the three plus signs? Sometime I also see one plus sign...
Is there any document talking about this? Or where could I refer to the code?
[cid:image001.jpg@01D0692E.43009C70]
Thanks!
Xiaoyong
Re: Sort order in Hive plan?
Posted by Prasanth Jayachandran <pj...@hortonworks.com>.
Hi
In the image that you had posted. There are 4 plus signs which means sorting happens on all four columns in key expression. Number of plus signs indicate the number of columns in key expressions that are used for sorting. Also minus sign indicate that sorting happens in descending order.
Thanks
Prasanth
On Fri, Mar 27, 2015 at 6:43 AM -0700, "Xiaoyong Zhu" <xi...@microsoft.com>> wrote:
Hi experts
When I am viewing the Hive plans, I notice that in Reduce Output Operators, there is a "property" named "sort order" and it's value is "+++" - may I know what's the meaning of the three plus signs? Sometime I also see one plus sign...
Is there any document talking about this? Or where could I refer to the code?
[cid:image003.jpg@01D068D6.DF717870]
Thanks!
Xiaoyong