| From: | Greg Stark <stark(at)mit(dot)edu> |
|---|---|
| To: | Peter Geoghegan <peter(at)2ndquadrant(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Hitoshi Harada <umi(dot)tanuki(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Memory usage during sorting |
| Date: | 2012-04-14 12:32:04 |
| Message-ID: | CAM-w4HOT2txOZ+nJLjSXDeJzK5h8V5Gm+L7JQoZ_tjcM-U=xjA@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Fri, Apr 13, 2012 at 7:01 PM, Peter Geoghegan <peter(at)2ndquadrant(dot)com> wrote:
> Well, timsort is specifically designed to take advantage of pre-sorted
> data. It does appear to have a lot of traction, as wikipedia points
> out:
I hadn't heard of it. But reading up on it it does seem like a good
fit for us. It trades some additional storage -- an array of pointers
into the sort array where in our case the pointers would be much
smaller than a whole SortTuple -- for fewer comparisons -- which in
our case are often much slower than a simple integer comparison.
--
greg
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