Comment by silvestrov

One thing I'd really like PostgreSQL to add is LIMIT on update statement as this makes batching easier. E.g.

    UPDATE user_profile
    SET followers_count = 0
    WHERE followers_count IS NULL
    LIMIT 10000

I don't care which rows gets updated, only that no more than 10000 rows get updated. After each UPDATE I will COMMIT and then repeat as long as the UPDATE returns a positive number of rows updated.

This makes it much easier to make small-ish batch updates and avoid locking all rows in the table.