On 21 December 2012 20:10, Noah Misch <noah@leadboat.com> wrote:
> I thought of one case where we do currently forget rd_newRelfilenodeSubid:
>
> BEGIN;
> TRUNCATE t;
> SAVEPOINT save;
> TRUNCATE t;
> ROLLBACK TO save;
That's a weird one. Aborting a subtransacton that sets it, when it was
already set.
The loss of rd_newRelfilenodeSubid in that case is deterministic, but
tracking the full complexity of multiple relations and multiple nested
subxids isn't worth the trouble for such rare cases [assumption].
I'd go for just setting an its_too_complex flag (with better name)
that we can use to trigger a message in COPY to say that FREEZE option
won't be honoured. That would then be completely consistent, rather
than the lack of deterministic behaviour that Robert rightly objects
to.
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