Re: Abbreviated keys for text cost model fix

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От Arthur Silva
Тема Re: Abbreviated keys for text cost model fix
Дата
Msg-id CAO_YK0WQvHvtL44oZ5mM01WmSqgqe6zGOD=hYoiUM4Gxvdb1VQ@mail.gmail.com
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Ответ на Re: Abbreviated keys for text cost model fix  (Jeremy Harris <jgh@wizmail.org>)
Ответы Re: Abbreviated keys for text cost model fix  (Jeremy Harris <jgh@wizmail.org>)
Список pgsql-hackers
<div dir="ltr"><br /><div class="gmail_extra"><br /><div class="gmail_quote">On Mon, Mar 2, 2015 at 8:04 PM, Jeremy
Harris<span dir="ltr"><<a href="mailto:jgh@wizmail.org" target="_blank">jgh@wizmail.org</a>></span> wrote:<br
/><blockquoteclass="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span
class="">On25/02/15 00:32, Jeremy Harris wrote:<br /> > On 23/02/15 16:40, Tomas Vondra wrote:<br /> >> On
22.2.201522:30, Peter Geoghegan wrote:<br /> >>> You should try it with the data fully sorted like this, but
withone<br /> >>> tiny difference: The very last tuple is out of order. How does that<br /> >>>
look?<br/> ><br /> > If this case is actually important, a merge-sort can take<br /> > significant advantage
ofthe partial order:<br /><br /></span>Presumably it is not, as nobody commented<br /> on the alleged 20 or 30x
speedup.<br/><div class="HOEnZb"><div class="h5"><br /><br /><br /><br /> --<br /> Sent via pgsql-hackers mailing list
(<ahref="mailto:pgsql-hackers@postgresql.org">pgsql-hackers@postgresql.org</a>)<br /> To make changes to your
subscription:<br/><a href="http://www.postgresql.org/mailpref/pgsql-hackers"
target="_blank">http://www.postgresql.org/mailpref/pgsql-hackers</a><br/></div></div></blockquote></div><br
/></div><divclass="gmail_extra">Does it always perform mergesort instead of quicksort when enabled?<br />Seems like the
casefor a hybrid sort (like timsort). I know there was some talk to replace quicksort with timsort back in 2012 but it
wasa deadend at the time.<br /></div></div> 

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