1) I have tried the option 1, set it to 1000MB. it looks like still the same.

2) I have found out the a wait type - CXPACKET (0422). May I...

-- Assumes trans_headerID is pk for table

UPDATE t SET CARD_NO = left(card_no,6)+'******'+right(card_no,4)

FROM trans_header t

INNER JOIN (

SELECT TOP 100000 trans_headerID

...

1) autogrowth settings is 1MB, can we change it while update is still running? what is the best size setting for this autogrowth.

2) It is a good idea to run...

Have you confirmed that the update is not being blocked ?

1) The update is not being blocked

2) The size of the .LDF file is increasing, but it is slow eg.

5.15GB...