Date: Mon, 18 Jan 2021 19:30:19 -0300
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Michael Paquier <michael@paquier.xyz>,
	pgsql-hackers@lists.postgresql.org
Subject: Re: Odd, intermittent failure in contrib/pageinspect
Message-ID: <20210118223019.GA2579@alvherre.pgsql>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <413923.1611006484@sss.pgh.pa.us>
User-Agent: Mutt/1.10.1 (2018-07-13)
Precedence: bulk

On 2021-Jan-18, Tom Lane wrote:

> Searching the buildfarm logs turned up exactly one previous occurrence,
> also on whelk [2].  So I'm not sure what to make of it.  Could the
> immediately preceding VACUUM FREEZE command have silently skipped this
> page for some reason?  That'd be a bug I should think.

Hmm, doesn't vacuum skip pages when they are pinned?  I don't think
VACUUM FREEZE would be treated especially -- only "aggressive"
wraparound would be an exception, IIRC.  This would reflect in the
relfrozenxid for the table after vacuum, but I'm not sure if there's a
decent way to make the regression tests reflect that.

> Also, not really a bug, but why is this test script running exactly
> the same query twice in a row?  If that's of value, and not just a
> copy-and-paste error, the comments sure don't explain why.  But what
> it looks like is that these queries were different when first added,
> and then 58b4cb30a5b made them the same when it probably should have
> removed one.

Agreed.

-- 
Álvaro Herrera                            39°49'30"S 73°17'W