From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
cc: pgsql-hackers@lists.postgresql.org, alexk@hintbits.com
Subject: Re: pgsql: Avoid spurious deadlocks when upgrading a tuple lock
In-reply-to: <20190615034337.GA24560@alvherre.pgsql>
References: <20190615034337.GA24560@alvherre.pgsql>
Comments: In-reply-to Alvaro Herrera <alvherre@2ndquadrant.com>
	message dated "Fri, 14 Jun 2019 23:43:37 -0400"
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Date: Sat, 15 Jun 2019 12:25:39 -0400
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Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> On 2019-Jun-14, Tom Lane wrote:
>> BTW, after looking around a bit I wonder if this complaint isn't
>> exposing an actual logic bug.  Shouldn't skip_tuple_lock have
>> a lifetime similar to first_time?

> I think there are worse problems here.  I tried the attached isolation
> spec.  Note that the only difference in the two permutations is that s0
> finishes earlier in one than the other; yet the first one works fine and
> the second one hangs until killed by the 180s timeout.  (s3 isn't
> released for a reason I'm not sure I understand.)

Ugh.

> I don't think I'm going to have time to investigate this deeply over the
> weekend, so I think the safest course of action is to revert this for
> next week's set.

+1.  This is an old bug, we don't have to improve it for this release.

			regards, tom lane