Re: Making Vars outer-join aware

Richard Guo <guofenglinux@gmail.com>

From: Richard Guo <guofenglinux@gmail.com>

To: Tom Lane <tgl@sss.pgh.pa.us>

Cc: Pg Hackers <pgsql-hackers@lists.postgresql.org>, "Finnerty, Jim" <jfinnert@amazon.com>

Date: 2023-01-30T09:56:38Z

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 →

Re-allow INDEX_VAR as rt_index in ChangeVarNodes().
- fbf80421ead5 16.0 landed
Fix thinkos in have_unsafe_outer_join_ref; reduce to Assert check.
- f50f029c497d 16.0 landed
Invent "join domains" to replace the below_outer_join hack.
- 3bef56e11650 16.0 landed
Do assorted mop-up in the planner.
- b448f1c8d83f 16.0 landed
Make Vars be outer-join-aware.
- 2489d76c4906 16.0 landed
Invent "multibitmapsets", and use them to speed up antijoin detection.
- e9e26b5e7166 16.0 landed
Add basic regression tests for semi/antijoin recognition.
- 0043aa6b8597 16.0 landed
Improve performance of adjust_appendrel_attrs_multilevel.
- 2f17b57017e5 16.0 landed
Refactor addition of PlaceHolderVars to joinrel targetlists.
- afa0ec30bfd1 16.0 landed
Use an explicit state flag to control PlaceHolderInfo creation.
- b3ff6c742f6c 16.0 landed
Make PlaceHolderInfo lookup O(1).
- 6569ca43973b 16.0 landed

On Tue, Jan 24, 2023 at 4:38 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:

> Richard, are you planning to review this any more?  I'm getting
> a little antsy to get it committed.  For such a large patch,
> it's surprising it's had so few conflicts to date.

Sorry for the delayed reply.  I don't have any more review comments at
the moment, except a nitpicking one.

In optimizer/README at line 729 there is a query as

    SELECT * FROM a
      LEFT JOIN (SELECT * FROM b WHERE b.z = 1) ss ON (a.x = b.y)
    WHERE a.x = 1;

I think it should be

    SELECT * FROM a
      LEFT JOIN (SELECT * FROM b WHERE b.z = 1) ss ON (a.x = ss.y)
    WHERE a.x = 1;

I have no objection to get it committed.

Thanks
Richard