Re: Get last generated serial sequence and set it up when explicit value is used

On Friday, November 20, 2020, Sebastien FLAESCH <sf(at)4js(dot)com> wrote:
>
> Is there any way to avoid the error produced by currval()?
>
>
No

> Ideally, currval() should return zero when no serial was produced yet.

I’d accept null, zero is a valid value.

>
> Is it possible to write that in a simple SQL expression so it can be used
> in
> the RETURNING clause of my INSERTs ?
>

Not that I can think of. Maybe as the docs suggest, just do an
unconditional setval()? You might be able to combine that with a
non-default isolation level (guessing here) to get close-enough behavior.
You are fighting the existing design of the feature, looking for an
in-between position of fast-and-concurrent (existing) and fully serialized
(where this would be mostly trivial to implement). I don’t know of such a
method.

David J.