Re: Doc patch for index access method function

On Fri, Aug 10, 2018 at 1:37 PM Alexander Korotkov
<a(dot)korotkov(at)postgrespro(dot)ru> wrote:
> On Fri, Aug 10, 2018 at 6:24 AM Tatsuro Yamada
> <yamada(dot)tatsuro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> >
> > Attached patch for fixing documents of "61.2. Index Access Method Functions" and
> > "61.6. Index Cost Estimation Functions".
> >
> > I added a variable "double *indexPages" introduced by commit 5262f7a4f to the documents and
> > also added its explanation. Please read and revise it because I'm a non-native English speaker.
>
> Good catch. It was overseen in 5262f7a4fc44, where parallel index
> scan was introduced.
>
> "This is used to adjust the estimate for the cost of the disk access."
>
> This sentence doesn't look correct for me. Cost of the disk access is
> estimated inside amcostestimate(). As I get, indexPages is used to
> estimate how effective parallel scan would be, because different
> workers pick different leaf pages. I'm going to adjust this sentence
> and commit this fix.

Pushed.

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Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company