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help / color / mirror / Atom feedFrom: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Surafel Temesgen <surafel3000@gmail.com>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Cc: Andrew Gierth <andrew@tao11.riddles.org.uk>
Subject: Re: FETCH FIRST clause WITH TIES option
Date: Thu, 28 Nov 2019 11:49:03 -0300
Message-ID: <20191128144903.GA30772@alvherre.pgsql> (raw)
In-Reply-To: <CALAY4q82MDk1cehn-n2sSPu0iOLttXGk4A_CdXHnUSnQpK5sFA@mail.gmail.com>
On 2019-Nov-28, Surafel Temesgen wrote:
> On Thu, Nov 28, 2019 at 12:36 AM Alvaro Herrera <alvherre@2ndquadrant.com>
> wrote:
>
> > I think you should add a /* fall-though */ comment after changing state.
> > Like this (this flow seems clearer; also DRY):
> >
> > if (!node->noCount &&
> > node->position - node->offset >= node->count)
> > {
> > if (node->limitOption == LIMIT_OPTION_COUNT)
> > {
> > node->lstate = LIMIT_WINDOWEND;
> > return NULL;
> > }
> > else
> > {
> > node->lstate = LIMIT_WINDOWEND_TIES;
> > /* fall-through */
> > }
> > }
> > else
> > ...
>
> changed
But you did not read my code snippet, did you ...?
> > I think you need to stare a that thing a little harder.
>
> This is because the new state didn't know about backward scan
> and there was off by one error it scan one position past to detect
> ties. The attached patch fix both
Oh, thanks, glad it was that easy.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: alvherre@2ndquadrant.com, surafel3000@gmail.com, tomas.vondra@2ndquadrant.com, andrew@tao11.riddles.org.uk
Subject: Re: FETCH FIRST clause WITH TIES option
In-Reply-To: <20191128144903.GA30772@alvherre.pgsql>
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