Re: Using quicksort for every external sort run

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От Greg Stark
Тема Re: Using quicksort for every external sort run
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Msg-id CAM-w4HMBpLLs1HiuiSz3MnGB9B9XVcJxpNGAeJeawOLpB-zEqw@mail.gmail.com
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Ответ на Re: Using quicksort for every external sort run  (Peter Geoghegan <pg@heroku.com>)
Ответы Re: Using quicksort for every external sort run  (Peter Geoghegan <pg@heroku.com>)
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Hm. Here is a log-log chart of those results (sorry for html mail). I'm not really sure if log-log is the right tool to use for a O(nlog(n)) curve though. 

I think the take-away is that this is outside the domain where any interesting break points occur. Maybe run more tests on the low end to find where the tapesort can generate a single tape and avoid the merge and see where the discontinuity is with quicksort for the various work_mem sizes. 

And can you calculate an estimate where the domain would be where multiple passes would be needed for this table at these work_mem sizes? Is it feasible to test around there?
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--
greg
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