Re: Index Skip Scan

Поиск
Список
Период
Сортировка
Искать
От
Jesper Pedersen
Тема
Re: Index Skip Scan
Дата
Msg-id
0b141c81-592b-cd43-fc6d-1b5ba0aaac57@redhat.com
Ответ на
Re: Index Skip Scan (Dmitry Dolgov)
Список
Дерево обсуждения
Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Re: Index Skip Scan Alexander Korotkov <a.korotkov@postgrespro.ru>
Re: Index Skip Scan Michael Paquier <michael@paquier.xyz>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Alexander Korotkov <a.korotkov@postgrespro.ru>
Re: Index Skip Scan Bhushan Uparkar <bhushan.uparkar@gmail.com>
Re: Index Skip Scan Thomas Munro <thomas.munro@enterprisedb.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Stephen Frost <sfrost@snowman.net>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Stephen Frost <sfrost@snowman.net>
Re: Index Skip Scan Andres Freund <andres@anarazel.de>
Re: Index Skip Scan Peter Geoghegan <pg@bowt.ie>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Thomas Munro <thomas.munro@enterprisedb.com>
Re: Index Skip Scan Peter Geoghegan <pg@bowt.ie>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Peter Geoghegan <pg@bowt.ie>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Re: Index Skip Scan James Coleman <jtc331@gmail.com>
Re: Index Skip Scan Andres Freund <andres@anarazel.de>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Jeff Janes <jeff.janes@gmail.com>
Re: Index Skip Scan Jeff Janes <jeff.janes@gmail.com>
Re: Index Skip Scan Thomas Munro <thomas.munro@gmail.com>
Re: Index Skip Scan Tomas Vondra <tomas.vondra@2ndquadrant.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Re: Index Skip Scan Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Floris Van Nee <florisvannee@Optiver.com>
Re: Index Skip Scan Floris Van Nee <florisvannee@Optiver.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Rafia Sabih <rafia.pghackers@gmail.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Floris Van Nee <florisvannee@Optiver.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan James Coleman <jtc331@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Pavel Stehule <pavel.stehule@gmail.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Pavel Stehule <pavel.stehule@gmail.com>
Re: Index Skip Scan Pavel Stehule <pavel.stehule@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Robert Haas <robertmhaas@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Sergei Kornilov <sk@zsrv.org>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Dmitry Dolgov <9erthalion6@gmail.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Re: Index Skip Scan Jesper Pedersen <jesper.pedersen@redhat.com>
Hi Dmitry,

On 06/19/2018 06:01 AM, Dmitry Dolgov wrote:
>> On 18 June 2018 at 19:31, Alexander Korotkov  wrote:
>> Is skip scan only possible for index-only scan?  I guess, that no.  We
>> could also make plain index scan to behave like a skip scan.  And it
>> should be useful for accelerating DISTINCT ON clause.  Thus, we might
>> have 4 kinds of index scan: IndexScan, IndexOnlyScan, IndexSkipScan,
>> IndexOnlySkipScan.  So, I don't think I like index scan nodes to
>> multiply this way, and it would be probably better to keep number
>> nodes smaller.  But I don't insist on that, and I would like to hear
>> other opinions too.
> 
> In one of patches I'm working on I had similar situation, when I wanted to
> split one node into two similar nodes (before I just extended it) and logically
> it made perfect sense. But it turned out to be quite useless and the advantage
> I've got wasn't worth it - and just to mention, those nodes had more differences
> than in this patch. So I agree that probably it would be better to keep using
> IndexOnlyScan.
> 

I looked at this today, and creating a new node (T_IndexOnlySkipScan) 
would make the patch more complex.

The question is if the patch should create such a node such that future 
patches didn't have to deal with refactoring to a new node to cover 
additional functionality.

Thanks for your feedback !

Best regards,
  Jesper

В списке pgsql-hackers по дате отправления
От: Robert Haas
Дата:
От: Tomas Vondra
Дата:
Сообщение: Re: WAL prefetch
FAQ