Re: FETCH FIRST clause PERCENT option

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От
Andres Freund
Тема
Re: FETCH FIRST clause PERCENT option
Дата
Msg-id
20180816143421.rxla4tonz2dx5xez@alap3.anarazel.de
Ответ на
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Дерево обсуждения
FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Andres Freund <andres@anarazel.de>
Re: FETCH FIRST clause PERCENT option Mark Dilger <hornschnorter@gmail.com>
Re: FETCH FIRST clause PERCENT option Andres Freund <andres@anarazel.de>
Re: FETCH FIRST clause PERCENT option Mark Dilger <hornschnorter@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Mark Dilger <hornschnorter@gmail.com>
Re: FETCH FIRST clause PERCENT option Mark Dilger <hornschnorter@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Vik Fearing <vik.fearing@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Vik Fearing <vik.fearing@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: Re: FETCH FIRST clause PERCENT option David Steele <david@pgmasters.net>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Andres Freund <andres@anarazel.de>
Re: FETCH FIRST clause PERCENT option Tom Lane <tgl@sss.pgh.pa.us>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Thomas Munro <thomas.munro@gmail.com>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Alvaro Herrera <alvherre@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Erik Rijkers <er@xs4all.nl>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Erik Rijkers <er@xs4all.nl>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Tom Lane <tgl@sss.pgh.pa.us>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Re: FETCH FIRST clause PERCENT option Vik Fearing <vik.fearing@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Michael Paquier <michael@paquier.xyz>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Jaime Casanova <jcasanov@systemguards.com.ec>
Re: FETCH FIRST clause PERCENT option David Steele <david@pgmasters.net>
Re: FETCH FIRST clause PERCENT option Jaime Casanova <jcasanov@systemguards.com.ec>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Ryan Lambert <ryan@rustprooflabs.com>
Re: FETCH FIRST clause PERCENT option Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Re: FETCH FIRST clause PERCENT option Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: FETCH FIRST clause PERCENT option Tom Lane <tgl@sss.pgh.pa.us>
Re: FETCH FIRST clause PERCENT option Andrew Gierth <andrew@tao11.riddles.org.uk>
Re: FETCH FIRST clause PERCENT option Andrew Gierth <andrew@tao11.riddles.org.uk>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Andres Freund <andres@anarazel.de>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Erik Rijkers <er@xs4all.nl>
Re: FETCH FIRST clause PERCENT option Surafel Temesgen <surafel3000@gmail.com>
Re: FETCH FIRST clause PERCENT option Thomas Munro <thomas.munro@enterprisedb.com>
Hi,

On 2018-08-16 17:27:45 +0300, Surafel Temesgen wrote:
> FETCH FIRST with PERCENT option is SQL standard that state limit count to
> be specified in a percentage in addition to specify it in exact count and
> listed as one of Major features simply not implemented yet in recent wiki
> page [1].
> 
> I implemented it by executing the query plan twice. One without limit
> filter to find the total number of row that will be feed to limit node so
> the exact limit count can be calculated and the query plan execute again
> with limit filter with newly calculated exact count .

Won't that have rather massive issues with multiple evaluations of
clauses in the query?  Besides being really expensive?

I think you'd have to instead spill the query results into a tuplestore
(like we do for FOR HOLD queries at end of xact), and then do the
computations based on that.

- Andres

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