Simon Riggs <simon@2ndquadrant.com> writes:
> On Mon, 2008-06-09 at 11:33 -0400, Tom Lane wrote:
>> No, we are running a large query to which the user *thinks* he knows the
>> answer. There are any number of reasons why he might be wrong.
> Of course. I should have said "to which we already know the answer" to
> indicate I'm passing on others' criticisms of us.
[ shrug... ] We don't know the answer either, and anyone who says
we do is merely betraying his ignorance of the number of ways to load
a foot-gun.
I don't have any confidence in the "checksum" proposal either, as it's
still naively assuming that changes in the data are the only possible
problem. Consider that you are loading the data into a new database,
which might be running under a different locale setting, might contain
a new implementation of a datatype with subtly (or not so subtly)
different semantics, or might just already contain data in the target
tables. pg_dump scripts are not nearly bright enough to defend against
these types of threats.
regards, tom lane