Re: Virtual generated columns

Alexander Lakhin <exclusion@gmail.com>

From: Alexander Lakhin <exclusion@gmail.com>
To: Peter Eisentraut <peter@eisentraut.org>, Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>, jian he <jian.universality@gmail.com>
Date: 2025-02-09T08:00:00Z
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. Expand virtual generated columns for ALTER COLUMN TYPE

  2. Eliminate code duplication in replace_rte_variables callbacks

  3. Expand virtual generated columns in the planner

  4. Virtual generated columns

  5. Additional tests for stored generated columns

  6. Improve generated_stored test

  7. Fix handling of CREATE DOMAIN with GENERATED constraint syntax

  8. Add pg_constraint rows for not-null constraints

  9. Put generated_stored test objects in a schema

  10. Rename regress test generated to generated_stored

  11. Small code simplification

  12. Remove useless code

  13. Remove useless initializations

  14. doc: Clarify that pg_attrdef also stores generation expressions

  15. Clean out column-level pg_init_privs entries when dropping tables.

  16. Re-implement the ereport() macro using __VA_ARGS__.

Hello Peter,

07.02.2025 14:34, Peter Eisentraut wrote:
> I've committed it.  Thanks.

Please look at a planner error with a virtual generated column triggered
by the following script:
CREATE TABLE t(a int, b int GENERATED ALWAYS AS (a * 1));

SELECT SUM(CASE WHEN t.b = 1 THEN 1 ELSE 1 END) OVER (PARTITION BY t.a)
FROM t AS t1 LEFT JOIN T ON true;

ERROR:  XX000: wrong varnullingrels (b) (expected (b 3)) for Var 2/1
LOCATION:  search_indexed_tlist_for_var, setrefs.c:2901

(I discovered this anomaly with SQLsmith.)

Best regards,
Alexander Lakhin
Neon (https://neon.tech)