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From: Ayush Tiwari <[email protected]>
To: Tender Wang <[email protected]>
Cc: [email protected]
Cc: Калинин Никита <[email protected]>
Cc: Michael Paquier <[email protected]>
Cc: Pierre Forstmann <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Tom Lane <[email protected]>
Subject: Re: BUG #19493: Assertion failure in pg_plan_advice with EXISTS subquery and DO_NOT_SCAN advice
Date: Wed, 27 May 2026 12:46:24 +0530
Message-ID: <CAJTYsWUsW6zm_5thDsmV=c9VLs-O==r1RusDDF7kCekV0AECDA@mail.gmail.com> (raw)
In-Reply-To: <CAHewXNkHsjOjaWUcdtrGTWeHK8f1N8=L434O0b9ecgtGaMFQrg@mail.gmail.com>
References: <[email protected]>
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	<CAHewXNkHsjOjaWUcdtrGTWeHK8f1N8=L434O0b9ecgtGaMFQrg@mail.gmail.com>

Hi,

On Wed, 27 May 2026 at 09:20, Tender Wang <[email protected]> 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


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