Re: pgsql: snapshot scalability: cache snapshots using a xact completion co

On 2020-08-18 13:52:46 +0900, Michael Paquier wrote:
> On Tue, Aug 18, 2020 at 04:30:21AM +0000, Andres Freund wrote:
> spurfowl and more animals are telling us that this commit has broken
> 2PC:
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=spurfowl&dt=2020-08-18%2004%3A31%3A11

It looks like it's a bit more subtle than outright breaking 2PC. We're
now at 3 out of 18 BF members having failed. I locally ran also quite a
few loops of the normal regression tests without finding an issue.

I'd written to Tom that I was planning to revert unless the number of
failures were lower than initially indicated. But that actually seems to
have come to pass (the failures are quicker to report because they don't
run the subsequent tests, of course). I'd like to let the failures
accumulate a bit longer, say until tomorrow Midday if I haven't figured
it out by then. With the hope of finding some detail to help pinpoint
the issue.

Greetings,

Andres Freund