Re: disfavoring unparameterized nested loops - Mailing list pgsql-hackers

From John Naylor
Subject Re: disfavoring unparameterized nested loops
Date
Msg-id CAFBsxsGYd0kYx_C80LuHNE1=fQdpNA9McFEF9hA+=MrwwowZ4g@mail.gmail.com
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In response to Re: disfavoring unparameterized nested loops  (Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>)
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On Fri, Jun 18, 2021 at 6:20 AM Ashutosh Bapat <ashutosh.bapat.oss@gmail.com> wrote:

> I have not come across many papers which leverage this idea. Googling
> "selectivity estimation confidence interval", does not yield many
> papers. Although I found [1] to be using a similar idea. So may be
> there's not merit in this idea, thought theoretically it sounds fine
> to me.
>
>
> [1] https://pi3.informatik.uni-mannheim.de/~moer/Publications/vldb18_smpl_synop.pdf

Well, that paper's title shows it's a bit too far forward for us, since we don't use samples during plan time (although that's a separate topic worth considering). From the references, however, this one gives some mathematical framing of the problem that lead to the thread subject, although I haven't read enough to see if we can get practical advice from it:

Y. E. Ioannidis and S. Christodoulakis. On the propagation of errors in the size of join results.

--
John Naylor
EDB: http://www.enterprisedb.com

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