Re: [HACKERS] [COMMITTERS] pgsql: Fix freezing of a dead HOT-updated tuple

On Fri, Oct 6, 2017 at 2:09 PM, Wong, Yi Wen <yiwong@amazon.com> wrote:
> Yesterday, I've been spending time with pg_visibility on the pages when I reproduce the issue in 9.6.
> None of the all-frozen or all-visible bits are necessarily set in problematic pages.

Since this happened yesterday, I assume it was with an unfixed version?

As you must have seen, Alvaro said he has a variant of Dan's original
script that demonstrates that a problem remains, at least on 9.6+,
even with today's fix. I think it's the stress-test that plays with
fillfactor, many clients, etc [1].

I've tried to independently reproduce the problem on the master
branch's current tip, with today's new fix, but cannot break things
despite trying many variations. I cannot reproduce the problem that
Alvaro still sees.

I'll have to wait until Alvaro posts his repro to the list before
commenting further, which I assume he'll post as soon as he can. There
doesn't seem to be much point in not waiting for that.

[1] https://postgr.es/m/20171005162402.jahqflf3mekileqm@alvherre.pgsql
-- 
Peter Geoghegan


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