Re: Spurious "apparent wraparound" via SimpleLruTruncate() rounding

From: Noah Misch <noah(at)leadboat(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Spurious "apparent wraparound" via SimpleLruTruncate() rounding
Date: 2019-02-17 04:09:13
Message-ID: 20190217040913.GA1305059@rfd.leadboat.com
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On Wed, Feb 13, 2019 at 11:26:23PM -0800, Noah Misch wrote:
> On further study, I was able to reproduce data loss

> Fixes are available:
>
> a. Fix the rounding in SimpleLruTruncate(). (The patch I posted upthread is
> wrong; I will correct it in a separate message.)

Here's a corrected version. I now delete a segment only if both its first
page and its last page are considered to precede the cutoff; see the new
comment at SlruMayDeleteSegment().

Attachment Content-Type Size
slru-truncate-modulo-v2.patch text/plain 4.3 KB

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