On Fri, Aug 10, 2018 at 6:24 AM Tatsuro Yamada
<yamada.tats...@lab.ntt.co.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.

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

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