Increase speed altering column on large table to NON NULL

I recently added a NULL-able bit column to a table which has close to 500 million rows. There's not a default on the column, however all inserts are specifying a value of 0 or 1, and I ran a one-time routine to assign 0 or 1 to all existing rows (updating the rows in small batches). Every row should now have a 0 or 1 in that column.

I want to make the bit column non-nullable however when I tried doing so via ALTER TABLE t1 ALTER COLUMN c1 bit not null, it started running for 3 minutes and I stopped it because it was blocking all reads to the table and I suspected it was going to take a long time to complete. It's possible it wouldn't take too long but I couldn't risk too much unavailability. The rollback itself took 6 minutes.

Do you have any suggestions on how I can make the column non-nullable without it taking potentially hours to complete? Additionally is there any way to estimate how long the ALTER TABLE ALTER COLUMN statement I started and then cancelled would take to complete?

I am using SQL Server 2017 Web Edition.

If you are on Enterprise Edition (EE) a better strategy might have been to add it as NOT NULL with a default of 0 or 1 (whichever is most common).

This is a metadata-only change in EE. Then update the ones needing to be flipped. This means fewer updates and no need to change the column nullability when finished. - martin-smith

StackExchange Database Administrators Q#240055, answer score: 12