Horton

Re: pg_plan_advice

Jacob Champion <jacob.champion@enterprisedb.com>

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From: Jacob Champion <jacob.champion@enterprisedb.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Dian Fay <di@nmfay.com>, Matheus Alcantara <matheusssilv97@gmail.com>, Jakub Wartak <jakub.wartak@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-12-12T01:11:09Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Add pg_plan_advice contrib module.

  2. Store information about Append node consolidation in the final plan.

  3. Store information about elided nodes in the final plan.

  4. Store information about range-table flattening in the final plan.

  5. Allow for plugin control over path generation strategies.

  6. Allow passing a pointer to GetNamedDSMSegment()'s init callback.

  7. Don't reset the pathlist of partitioned joinrels.

On Tue, Dec 9, 2025 at 11:46 AM Robert Haas <robertmhaas@gmail.com> wrote:
> By the way, if your fuzzer can also
> produces some things to add contrib/pg_plan_advice/sql for cases like
> this, that would be quite helpful. Ideally I would have caught this
> with a manually-written test case, but obviously that didn't happen.

Sure! (They'll need to be golfed down.) Here are three entries that
hit the crash, each on its own line:

> join_order(qoe((nested_l oindex_scanp_plain))se(nested_loop_plain)nested_loo/_pseq_scanlain)
> join_order(qoe((nested_loop_plain))se(nested_loop_plain)nesemij/insted_loop_plain)
> gather(gather(gar(g/ther0))gtaher(gathethga))

Something the fuzzer really likes is zero-length identifiers ("").
Maybe that's by design, but I thought I'd mention it since the
standard lexer doesn't allow that and syntax.sql doesn't exercise it.

> > It doesn't know that area is guaranteed to be non-NULL, so it can't
> > prove that ca_pointer is initialized.
>
> I don't know what to do about that. I can understand why it might be
> unable to prove that, but I don't see an obvious way to change the
> code that would make life easier. I could add Assert(area != NULL)
> before the call to pgpa_make_collected_advice() if that helps.

With USE_ASSERT_CHECKING, that should help, but I'm not sure if it
does without. (I could have sworn there was a conversation about that
at some point but I can't remember any of the keywords.) Could also
just make a dummy assignment. Or tag pg_plan_advice_dsa_area() with
__attribute__((returns_nonnull)), but that's more portability work.

--Jacob