Horton

Re: Memory usage during sorting

Greg Stark <stark@mit.edu>

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From: Greg Stark <stark@mit.edu>
To: Peter Geoghegan <peter@2ndquadrant.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Jeff Janes <jeff.janes@gmail.com>, Hitoshi Harada <umi.tanuki@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2012-04-14T12:32:04Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Improve performance of our private version of qsort. Per recent testing,

  2. Further performance improvements in sorting: reduce number of comparisons

On Fri, Apr 13, 2012 at 7:01 PM, Peter Geoghegan <peter@2ndquadrant.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