PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> The documentation says `transaction_timestamp()` and
> `statement_timestamp()` return the same value during the first statement of
> a
> transaction. With a parameterized query executed as the first command on a
> fresh autocommit connection, they differ.
Strictly speaking, that depends on which steps of an extended-protocol
query count as separate statements. But I don't think we're going to
modify this documentation to dive into details as abstruse as that;
it would merely confuse the same people the comment is meant to help.
regards, tom lane