"Zubkovsky, Sergey" <Sergey.Zubkovsky@transas.com> writes:
> I've detected that a result value of pg_total_relation_size() for an
> actively updated table might be significantly differ from a result that
> is returned after explicit CHECKPOINT command execution.
Uh, can you show a specific example of what you mean?
> I understand the reasons of such behavior: cache buffers must be flushed
> in order to be sure that pg_total_relation_size() result will be like we
> expect.
I wouldn't think so. The space for a page is allocated immediately when
needed --- its *contents* might not be up to date, but that shouldn't
affect pg_total_relation_size.
regards, tom lane