Question : Why RTRIM so slow on UPDATE

Hi,

I have a table in SQL 2008 with an index on field1. It has over 6,000,000 records. When I attempt to do this:

1: 2:

UPDATE my_table SET field1 = RTRIM(field1)

It just runs forever and ever. I don't understand why the index doesn't get picked up, it seems straightforward, any ideas? Thanks!

Answer : Why RTRIM so slow on UPDATE

What about this?  Part of the issue might be that it has to keep up with the indexing for all six million records.  

ALTER Your_Index_Name ON my_table DISABLE

UPDATE my_table
SET field1 = RTRIM(field1)

ALTER INDEX ALL ON my_table REBUILD