Horton
Menu

Re: PageIsAllVisible()'s trustworthiness in Hot Standby

Pavan Deolasee <pavan.deolasee@gmail.com>

View thread
From: Pavan Deolasee <pavan.deolasee@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2012-12-12T17:31:14Z
Lists: pgsql-hackers

Attachments

On Wed, Dec 12, 2012 at 1:35 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Tue, Dec 4, 2012 at 12:10 PM, Pavan Deolasee
> <pavan.deolasee@gmail.com> wrote:
>> Hmm. Yeah, I do not have guts to prove that either. I'll probably write up a
>> comment for your consideration to explain why we don't trust PD_ALL_VISIBLE
>> in Hot standby for seq scans, but still trust VM for index-only scans.
>
> Sure.
>

Here is a small patch that adds comments to heap scan code explaining
why we don't trust the all-visible flag in the page, still continue to
support index-only scans on hot standby.

Thanks,
Pavan

-- 
Pavan Deolasee
http://www.linkedin.com/in/pavandeolasee

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Prevent index-only scans from returning wrong answers under Hot Standby.