Re: Index Skip Scan (new UniqueKeys) - Mailing list pgsql-hackers

From Dmitry Dolgov
Subject Re: Index Skip Scan (new UniqueKeys)
Date
Msg-id 20200629120709.52w2zi36mtzyliv2@localhost
Whole thread Raw
In response to Re: Index Skip Scan (new UniqueKeys)  (Andy Fan <zhihui.fan1213@gmail.com>)
Responses RE: Index Skip Scan (new UniqueKeys)
List pgsql-hackers
> On Thu, Jun 11, 2020 at 04:14:07PM +0800, Andy Fan wrote:
>
> I just get the rough idea of patch, looks we have to narrow down the
> user cases where we can use this method. Consider the below example:

Hi

Not exactly narrow down, but rather get rid of wrong usage of skipping
for index scan. Since skipping for it was added later than for index
only scan I can imagine there are still blind spots, so good that you've
looked. In this particular case, when index expressions do not fully
cover those expressionse result need to be distinct on, skipping just
doesn't have enough information and should not be used. I'll add it to
the next version, thanks!



pgsql-hackers by date:

Previous
From: Julien Rouhaud
Date:
Subject: Re: track_planning causing performance regression
Next
From: "higuchi.daisuke@fujitsu.com"
Date:
Subject: RE: [Bug fix]There is the case archive_timeout parameter is ignoredafter recovery works.