Gokulakannan Somasundaram <gokul007@gmail.com> writes:
> a) We are already going from table to index to do unique checks. This is the
> same thing, which we will do to go and update the snapshot in the indexes.
No, it is not the same thing. Updating index snapshots requires being
able to *re-find* a previously made index entry for the current row.
And it has to be done 100% reliably. The worst that happens if an index
entry is not found when it should be during a uniqueness check is that
the uniqueness constraint is not enforced properly; which is bad but it
doesn't lead to internally-inconsistent data structures.
> b) The way, it should work would be to have a check on whether the operator
> is broken / function is volatile and put the onus on the user to make sure
> that they are updated correctly.
Pretending the problem doesn't exist doesn't make it go away ...
regards, tom lane
