Horton

Re: Wrong rows estimations with joins of CTEs slows queries by more than factor 500

Richard Guo <guofenglinux@gmail.com>

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From: Richard Guo <guofenglinux@gmail.com>
To: vignesh C <vignesh21@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Alexander Lakhin <exclusion@gmail.com>, Jian Guo <gjian@vmware.com>, Tomas Vondra <tomas.vondra@enterprisedb.com>, Hans Buschmann <buschmann@nidsa.net>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>, Zhenghua Lyu <zlyu@vmware.com>
Date: 2024-01-29T02:30:52Z
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. Allow examine_simple_variable() to work on INSERT RETURNING Vars.

  2. Extract column statistics from CTE references, if possible.

  3. Remove SQL regression tests for GUCs related to NO_SHOW_ALL

On Sat, Jan 27, 2024 at 10:08 AM vignesh C <vignesh21@gmail.com> wrote:

> On Mon, 8 Jan 2024 at 22:21, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >
> > Richard Guo <guofenglinux@gmail.com> writes:
> > > On Sun, Jan 7, 2024 at 6:41 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > >> Thanks for the report!  I guess we need something like the attached.
> >
> > > +1.
> >
> > Pushed, thanks for looking at it.
>
> I have changed the status of the commitfest entry to "Committed" as I
> noticed the patch has already been committed.


Well, the situation seems a little complex here.  At first, this thread
was dedicated to discussing the 'Examine-simple-variable-for-Var-in-CTE'
patch, which has already been pushed in [1].  Subsequently, I proposed
another patch 'Propagate-pathkeys-from-CTEs-up-to-the-outer-query' in
[2], which is currently under review and is what the commitfest entry
for.  Later on, within the same thread, another patch was posted as a
fix to the first patch and was subsequently pushed in [3].  I believe
this sequence of events might have led to confusion.

What is the usual practice in such situations?  I guess I'd better to
fork a new thread to discuss my proposed patch which is about the
'Propagate-pathkeys-from-CTEs-up-to-the-outer-query'.

[1] https://www.postgresql.org/message-id/754093.1700250120%40sss.pgh.pa.us
[2]
https://www.postgresql.org/message-id/CAMbWs49gAHeEOn0rpdUUYXryaa60KZ8JKwk1aSERttY9caCYkA%40mail.gmail.com
[3] https://www.postgresql.org/message-id/1941515.1704732682%40sss.pgh.pa.us

Thanks
Richard