Horton

Re: [PoC] Reducing planning time when tables have many partitions

Yuya Watari <watari.yuya@gmail.com>

View thread
From: Yuya Watari <watari.yuya@gmail.com>
To: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
Cc: Thom Brown <thom@linux.com>, David Rowley <dgrowleyml@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Zhang Mingli <zmlpostgres@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2023-07-28T08:49:04Z
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. Update wording in optimizer/README for EquivalenceClasses

  2. Speedup child EquivalenceMember lookup in planner

  3. Allow planner to use Merge Append to efficiently implement UNION

  4. Remove trailing zero words from Bitmapsets

  5. Make Vars be outer-join-aware.

  6. Avoid making commutatively-duplicate clauses in EquivalenceClasses.

Hello,

On Fri, Jul 28, 2023 at 1:27 PM Andrey Lepikhov
<a.lepikhov@postgrespro.ru> wrote:
> Sorry for this. It was definitely a false alarm. In this patch,
> assertion checking adds much overhead. After switching it off, I found
> out that this feature solves my problem with a quick pass through the
> members of an equivalence class. Planning time results for the queries
> from the previous letter:
> 1 - 0.4s, 2 - 1.3s, 3 - 1.3s; (with the patches applied)
> 1 - 5s; 2 - 8.7s; 3 - 22s; (current master).
>
> I have attached flamegraph that shows query 2 planning process after
> applying this set of patches. As you can see, overhead at the
> equivalence class routines has gone.

I really appreciate testing the patches and sharing your results. The
results are interesting because they show that our optimization
effectively reduces planning time for your workload containing
different queries than I have used in my benchmarks.

Thank you again for reviewing this.

-- 
Best regards,
Yuya Watari