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

Hi,

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,