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Message-ID: <6d0a3ba80708280455u763d09b9m48e3091c57544b8c@mail.gmail.com>
Date: Tue, 28 Aug 2007 13:55:26 +0200
From: "goran bogdanovic" <goran00@gmail.com>
To: "Ghassan Salem" <salem.ghassan@gmail.com>
Subject: Re: 10g ORDER BY Performance
Cc: oracle-l <oracle-l@freelists.org>
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the parameter "_gby_hash_aggregation_enabled" is related to case where
'group by' in query (without 'order by' clause) was returning ordered data
in 9i using one method and in 10g is using another...the group by clause in
10g is enhanced to allow a hash algorithm to be used instead of  sorting
algorithm to group the data.


On 8/24/07, Ghassan Salem <salem.ghassan@gmail.com> wrote:
>
> It's not the new sort that doing this, it's the 'hash group by'
> try disabling it using
> alter ... set "_gby_hash_aggregation_enabled"=false;
>
>
> On 8/24/07, goran bogdanovic <goran00@gmail.com> wrote:
> >
> > http://jonathanlewis.wordpress.com/2007/06/03/sorting/
> >
> > you may set it for a session too:
> >
> > alter session set "_newsort_enabled"=false;
> >
>
>

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<br>the parameter &quot;_gby_hash_aggregation_enabled&quot; is related to case where &#39;group by&#39; in query (without &#39;order by&#39; clause) was returning ordered data in 9i using one method and in 10g is using another...the group by clause in 10g is enhanced to allow a hash algorithm to be used instead of&nbsp; sorting algorithm to group the data.
<br><br><br><div><span class="gmail_quote">On 8/24/07, <b class="gmail_sendername">Ghassan Salem</b> &lt;<a href="mailto:salem.ghassan@gmail.com">salem.ghassan@gmail.com</a>&gt; wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
It&#39;s not the new sort that doing this, it&#39;s the &#39;hash group by&#39; <br>try disabling it using<br>alter ... set &quot;_gby_hash_aggregation_enabled&quot;=false;<div><span class="q" id="q_11498663f3747726_1"><br>
<br><br><div><span class="gmail_quote">On 8/24/07, 
<b class="gmail_sendername">goran bogdanovic</b> &lt;<a href="mailto:goran00@gmail.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">goran00@gmail.com</a>&gt; wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">

<a href="http://jonathanlewis.wordpress.com/2007/06/03/sorting/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://jonathanlewis.wordpress.com/2007/06/03/sorting/</a><br><br>you may set it for a session too:
<br><br><font face="Courier">
          alter session set &quot;_newsort_enabled&quot;=false;</font><br>
</blockquote></div><br>
</span></div></blockquote></div><br>

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