Hi,
On 2015-05-10 16:01:53 -0400, Tom Lane wrote:
> The cause of the problem seems to be that the UPDATE performs a HOT update
> of the new tuple, leaving in this case a dead tuple at (0,2) that is HOT
> updated by (0,3). When unique_key_recheck() is invoked for (0,2), it
> believes, correctly, that it has to perform the recheck anyway ... but it
> tells check_exclusion_constraint that the check is being performed for
> (0,2). So the index search inside check_exclusion_constraint finds the
> live tuple at (0,3) and thinks that is a conflict.
Heh, it's curious that this wasn't found up until now. I also wonder if
this might be related to the spurious violations Peter G. has been
observing...
> The attached patch seems to fix the problem without breaking any existing
> regression tests, but I wonder if anyone can see a hole in it.
Looks good to me.
Greetings,
Andres Freund