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  1. Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK constraints

  1. pgsql: Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK

    Peter Eisentraut <peter@eisentraut.org> — 2026-02-24T09:42:06Z

    Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK constraints

Previously, changing the generation expression of a virtual column was
prohibited if the column was referenced by a CHECK constraint.  This
lifts that restriction.

RememberAllDependentForRebuilding within ATExecSetExpression will
rebuild all the dependent constraints, later ATPostAlterTypeCleanup
queues the required AlterTableStmt operations for ALTER TABLE Phase 3
execution.

Overall, ALTER COLUMN SET EXPRESSION on virtual columns may require
scanning the table to re-verify any associated CHECK constraints, but
it does not require a table rewrite in ALTER TABLE Phase 3.

Author: jian he <jian.universality@gmail.com>
Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Discussion: https://postgr.es/m/CACJufxH3VETr7orF5rW29GnDk3n1wWbOE3WdkHYd3iPGrQ9E_A@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/f80bedd52b1501de51b7180cd817e3e1fc31429d

Modified Files
--------------
doc/src/sgml/ref/alter_table.sgml               |  3 ++
src/backend/commands/tablecmds.c                | 25 ++++------------
src/test/regress/expected/generated_virtual.out | 39 +++++++++++++++++++++----
src/test/regress/sql/generated_virtual.sql      | 16 ++++++++--
4 files changed, 56 insertions(+), 27 deletions(-)

  2. typo in alter_table.sgml (was: Re: pgsql: Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK)

    Erik Rijkers <er@xs4all.nl> — 2026-02-26T14:16:22Z

    Op 2/24/26 om 10:42 schreef Peter Eisentraut:
> Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK constraints
> [...]
> 
> Branch
> ------
> master
> 
> Details
> -------
> https://git.postgresql.org/pg/commitdiff/f80bedd52b1501de51b7180cd817e3e1fc31429d
> 
> Modified Files
> --------------
> doc/src/sgml/ref/alter_table.sgml               |  3 ++

Hi,

Typo in doc/src/sgml/ref/alter_table.sgml:


-      Replacing the expression of a virtual generated column do not 
require a
+      Replacing the expression of a virtual generated column does not 
require a

Thanks,

Erik

  3. Re: typo in alter_table.sgml (was: Re: pgsql: Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK)

    Chao Li <li.evan.chao@gmail.com> — 2026-02-26T23:21:01Z

    
> On Feb 26, 2026, at 22:16, Erik Rijkers <er@xs4all.nl> wrote:
> 
> Op 2/24/26 om 10:42 schreef Peter Eisentraut:
>> Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK constraints
>> [...]
>> Branch
>> ------
>> master
>> Details
>> -------
>> https://git.postgresql.org/pg/commitdiff/f80bedd52b1501de51b7180cd817e3e1fc31429d
>> Modified Files
>> --------------
>> doc/src/sgml/ref/alter_table.sgml               |  3 ++
> 
> Hi,
> 
> Typo in doc/src/sgml/ref/alter_table.sgml:
> 
> 
> -      Replacing the expression of a virtual generated column do not require a
> +      Replacing the expression of a virtual generated column does not require a
> 
> Thanks,
> 
> Erik
> 
> <alter_table.sgml.20260226.diff>

“Do” -> “does”, looks like a correct grammar fix to me.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/

  4. Re: typo in alter_table.sgml (was: Re: pgsql: Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK)

    Michael Paquier <michael@paquier.xyz> — 2026-03-02T02:35:02Z

    On Thu, Feb 26, 2026 at 03:16:22PM +0100, Erik Rijkers wrote:
> -      Replacing the expression of a virtual generated column do not require
> a
> +      Replacing the expression of a virtual generated column does not
> require a

Thanks.  This applies only to HEAD.  Grabbed that for later.
--
Michael