On Thursday, July 11, 2024, PG Doc comments form <
noreply@postgresql.org> wrote:
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/16/plpgsql-transactions.html
Description:
https://www.postgresql.org/docs/current/plpgsql-transactions.html
In this section nothing mentioned that a savepoint (a subtransaction) will
not work inside plpgsql.
Correct, we prefer to just document how things work. 43.2 does mention that blocks form subtransactions.
Also need to say, that "begin
end" block with "exception" handler will implicitly save and release
savepoints.
A savepoint is an SQL command giving you access to subtransactions. Plpgsql doesn’t need or use it, it has a direct access to subtransactions though in a limited/different way. In short, even if this worked this way we wouldn’t document such an implementation detail.
I suppose we could draw analogies to savepoints, or maybe mention subtransactions again in the procedure transactions chapter. Namely by explaining why the last limitation on that page exists, which I presume is related to subtransactions. But really that page is meant to show how procedures can use commit/rollback to anffect the outer transaction unlike all other plpgsql code which simply gets block-based subtransactions management as previously described. It does this sufficiently and need not be cluttered by subtransaction discussion in any meaningful detail.
David J.
