Re: pg_dump future problem.

Philip Warner <pjw(at)rhyme(dot)com(dot)au> writes:
> At 10:10 AM 4/05/2003 -0400, Tom Lane wrote:
>> And the is_called flag fits into this where?

> My recollection is that is_called is used to cover the boundary case where
> the 'current' value should not be incremented before being returned, but my
> memory is hazy. If this is the case, can we not just set it to true and set
> the value to (next - 1) unless (next - 1) < minv, in which case we set it
> to minv and set is_called to false?

This would fail to cover the case where the user has used setval() to
set is_called false and last_value to something other than minv.

> Note that for the purpose of serial values we do not need to set the
> sequence exactly as it was internally, we just need to make sure that the
> next allocated value will be what we expect.

I disagree with the notion that pg_dump need not dump legal
configurations of the database.

ISTM the real issue here is that we don't want pg_dump dumps to
hard-wire knowledge of the algorithm for deriving a sequence name from a
table and column name. Why not attack that straightforwardly: provide a
backend function that computes one from the other? Then the SETVAL
calls could become something like

SELECT setval(serial_seq_name('table', 'column'), 42, true);

and we're not sacrificing anything --- nor going through the very
substantial overhead of creating a new ALTER TABLE variant.

regards, tom lane