DECLARE @rows int
DECLARE @batchsize int
SET @rows = 1
SET @batchsize = 10000 -- whatever size you find appropriate

WHILE @rows > 0 
BEGIN
    UPDATE TOP(@batchsize) a
    SET a.field1 = b.field1
    FROM table1 a
    INNER JOIN table2 b 
        ON a.id = b.id
    WHERE a.status = -1

    SET @rows = @@ROWCOUNT

    BACKUP LOG ...
END

DECLARE @rows int
DECLARE @batchsize int
SET @rows = 1
SET @batchsize = 10000 -- whatever size you find appropriate

WHILE @rows > 0 
BEGIN
    UPDATE TOP(@batchsize) a
    SET a.field1 = b.field1
    FROM table1 a
    INNER JOIN table2 b 
        ON a.id = b.id
    WHERE a.status = -1
    AND a.field1 != b.field1
--AND ISNULL(a.field1,'') != ISNULL(b.field1,'') --is there nulls?

    SET @rows = @@ROWCOUNT

    BACKUP LOG ...
END

UPDATE a
SET a.field1 = b.field1  
FROM table1 a 
INNER JOIN table2 b ON a.id = b.id AND a.status = -1
where (a.datekey > '20100101') And (a.field1 != b.field1) And (b.field1 IS NOT NULL) 
Go