Is an UPDATE of a whole table safe in a SurrealDB migration?

UPDATE of every record in a table

Warning: the statement succeeds, then writes fail, access changes, or the table is held up.

What happens

Observed on SurrealDB 3.0.2: an UPDATE over a table where one record fails its field TYPE rolls back every record the statement had already changed.

Why it is dangerous on a populated table

SurrealDB checks a schema change against new writes, not the records already stored, so an empty table hides it: on a populated one every old record is a write waiting to fail, and whole-table work runs for the length of the table in one transaction.

Fires on

UPDATE user SET plan = 'free';

The safe pattern

UPDATE user SET plan = 'free' WHERE plan IS NONE;

Fixtures

The rule ships with these files and the test suite runs them on every change: the first set must fire, the second must stay silent.

UPDATE user UNSET legacy_flag;

UPDATE user SET plan = 'free';

DEFINE TABLE plan_defaults SCHEMALESS;
UPDATE plan_defaults SET tier = 'free';

UPDATE user:admin SET plan = 'enterprise';

UPDATE user:1..100 SET plan = 'free';

UPDATE user SET plan = 'free' WHERE plan IS NONE;

How to check locally

npx bolvrk check migration.surql --engine=surrealdb