Horton

Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK constraints

Peter Eisentraut <peter@eisentraut.org>

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Commit: f80bedd52b1501de51b7180cd817e3e1fc31429d
Author: Peter Eisentraut <peter@eisentraut.org>
Date: 2026-02-24T09:32:05Z
Releases: 19 (unreleased) 
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

Files

PathChange+/−
doc/src/sgml/ref/alter_table.sgml modified +3 −0
src/backend/commands/tablecmds.c modified +6 −19
src/test/regress/expected/generated_virtual.out modified +33 −6
src/test/regress/sql/generated_virtual.sql modified +14 −2

Discussion