Florian Pflug <fgp@phlo.org> writes:
> All in all, I believe that SHARE and UPDATE row-level locks should be
> changed to cause concurrent UPDATEs to fail with a serialization
> error.
I don't see an argument for doing that for FOR SHARE locks, and it
already happens for FOR UPDATE (at least if the row actually gets
updated). AFAICS this proposal mainly breaks things, in pursuit of
an unnecessary and probably-impossible-anyway goal of making FK locking
work with only user-level snapshots.
regards, tom lane
