Re: Index Skip Scan

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От
Dilip Kumar
Тема
Re: Index Skip Scan
Дата
в 04:25:42
Msg-id
CAFiTN-sEfZYugCQ9_1EM9qZTePpSZ3SfGztd4qkXGu0_B4MfqQ@mail.gmail.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>


On Fri, 15 May 2020 at 6:06 PM, Dmitry Dolgov <9erthalion6@gmail.com> wrote:
> On Wed, May 13, 2020 at 02:37:21PM +0530, Dilip Kumar wrote:
>
> + if (_bt_scankey_within_page(scan, so->skipScanKey, so->currPos.buf, dir))
> + {
>
> Here we expect whether the "next" unique key can be found on this page
> or not, but we are using the function which suggested whether the
> "current" key can be found on this page or not.  I think in boundary
> cases where the high key is equal to the current key, this function
> will return true (which is expected from this function), and based on
> that we will simply scan the current page and IMHO that cost could be
> avoided no?

Yes, looks like you're right, there is indeed an unecessary extra scan
happening. To avoid that we can see the key->nextkey and adjust higher
boundary correspondingly. Will also add this into the next rebased
patch, thanks!

Great thanks!
--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com
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