> The proper fix is to acquire SIREAD on the relation.
That's a way to fix it, but I am not sure that it is the proper way to
do it because it locks way more than needed.
One issue is that now this takes a whole relation lock for UPDATE ...
WHERE CURRENT OF, which can cause false-positive abort of cursor
loops. I think this part is fixable with an extended condition.
Also after I looked into this a bit more today, cb5b28613d5 in 2020
introduced SO_TYPE_TIDSCAN exactly to prevent full relation locks.
Maybe the reasoning of that commit was wrong, and we indeed need whole
relation locks there, but it doesn't seem like a trivial decision to
me.
