Re: BUG #19493: Assertion failure in pg_plan_advice with EXISTS subquery and DO_NOT_SCAN advice

Hi,

On Wed, 27 May 2026 at 09:20, Tender Wang <tndrwang(at)gmail(dot)com> wrote:

> Hi, all
>
> I find an easier way as follows:
> diff --git a/contrib/pg_plan_advice/pgpa_trove.c
> b/contrib/pg_plan_advice/pgpa_trove.c
> index ca69f3bd3df..64af4b1435b 100644
> --- a/contrib/pg_plan_advice/pgpa_trove.c
> +++ b/contrib/pg_plan_advice/pgpa_trove.c
> @@ -179,7 +179,6 @@ pgpa_build_trove(List *advice_items)
> * but in the future this
> might not be true, e.g. a custom
> * scan could replace a join.
> */
> - Assert(target->ttype ==
> PGPA_TARGET_IDENTIFIER);
>
> pgpa_trove_add_to_slice(&trove->scan,
>
> item->tag, target);
> }
>

Thanks for checking this.

I agree that removing the assertion looks like the better approach.

Keeping the original target tree seems preferable. As you noted,
pgpa_identifier_matches_target() already handles non-identifier targets by
checking their descendants. pgpa_trove_add_to_hash() does the same when
building the lookup table, so a grouped target such as ((a)) should still be
indexed and matched through its child identifier while preserving the
original
shape for output.

So I think the assertion in pgpa_build_trove() is too strict, and the nearby
comment should be adjusted to avoid saying/implying that scan advice always
has a direct identifier target.

Regards,
Ayush