MG14 — ALTER COLUMN SET NOT NULL scans the table under a lock

Group: Migration safety · Auto-fixable: no

SET NOT NULL scans every existing row to verify the constraint while holding a lock. Add a CHECK (col IS NOT NULL) NOT VALID, VALIDATE it (a weaker lock), then SET NOT NULL — Postgres reuses the validated check and skips the scan.

Example

bad:  ALTER TABLE t ALTER COLUMN c SET NOT NULL;

Configure

Disable this rule in banshee.toml:

[lint]
exclude = ["MG14"]

Or silence one line with -- noqa: MG14. See Linting.