Thread: Doc patch for index access method function
Hi, 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. Regards, Tatsuro Yamada NTT Open Source Software Center
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Hi! On Fri, Aug 10, 2018 at 6:24 AM Tatsuro Yamada <yamada.tatsuro@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
On Fri, Aug 10, 2018 at 1:37 PM Alexander Korotkov <a.korotkov@postgrespro.ru> wrote: > On Fri, Aug 10, 2018 at 6:24 AM Tatsuro Yamada > <yamada.tatsuro@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. Pushed. ------ Alexander Korotkov Postgres Professional: http://www.postgrespro.com The Russian Postgres Company
Hi Alexander, On 2018/08/10 20:27, Alexander Korotkov wrote: > On Fri, Aug 10, 2018 at 1:37 PM Alexander Korotkov > <a.korotkov@postgrespro.ru> wrote: >> On Fri, Aug 10, 2018 at 6:24 AM Tatsuro Yamada >> <yamada.tatsuro@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. > > Pushed. I agree the sentence you corrected. Thanks for taking your time! Tatsuro Yamada NTT Open Source Software Center