From: Noah Misch <noah@leadboat.com>
To: pgsql-hackers@postgresql.org
Subject: Re: Spurious "apparent wraparound" via SimpleLruTruncate() rounding
Date: Sun, 10 Feb 2019 21:13:49 -0800
Message-ID: <20190211051349.GA952299@rfd.leadboat.com> (raw)
In-Reply-To: <20190202083822.GC32531@gust.leadboat.com>
References: <20190202083822.GC32531@gust.leadboat.com>
On Sat, Feb 02, 2019 at 03:38:22AM -0500, Noah Misch wrote:
> The main consequence is the false alarm. A prudent DBA will want to react to
> true wraparound, but no such wraparound has occurred. Also, we temporarily
> waste disk space in pg_xact. This feels like a recipe for future bugs. The
> fix I have in mind, attached, is to change instances of
> ctl->PagePrecedes(FIRST_PAGE_OF_SEGMENT, ROUNDED_cutoffPage) to
> ctl->PagePrecedes(LAST_PAGE_OF_SEGMENT, cutoffPage). I'm inclined not to
> back-patch this; does anyone favor back-patching?
To avoid wasting more of anyone's time: that patch is bad; I'll update this
thread when I have something better.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: noah@leadboat.com
Subject: Re: Spurious "apparent wraparound" via SimpleLruTruncate() rounding
In-Reply-To: <20190211051349.GA952299@rfd.leadboat.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox