What is the quickest way to reset a column to a specific value? I have 30 million rows inside a sql server database where I've added a simple tagging column. One character allowing null. I did add an index for the column. 

I use it to keep track of which rows have been processed for a data extraction. During the initial development I will be restarting the extraction process from scratch (several times) and need to reset the value to '1'.

Being a neophyte database developer (who am I kidding...), my first attempt used a simple update script to reset the value of '2' (the I've processed this row) to a '1'. The first time I ran the script it executed in about 5 minutes. The last time I executed - it took 45 minutes. There has to be a better way.

Is it possible for me to speed this up by completely removing the column and recreating it with a default value of '1'? Will the speed stay consistent? 

-- UPDATE ---

The next time I need to do this I'm going to try the following:

ALTER TABLE acmewidgets DROP COLUMN LegacyExtract;
ALTER TABLE acmewidgets
        ADD LegacyExtract CHAR NOT NULL DEFAULT (1);
Used the following and it executes in 41 seconds ! 

USE AcmeDatabase

DROP INDEX IF EXISTS IX_LegacyExtract ON AcmeWidgetTable

ALTER TABLE AcmeWidgetTable DROP CONSTRAINT IF EXISTS DF_Legacy_Extract

ALTER TABLE AcmeWidgetTable DROP COLUMN IF EXISTS LegacyExtract

GO

ALTER TABLE AcmeWidgetTable CHAR NOT NULL CONSTRAINT DF_Legacy_Extract DEFAULT (0)

GO

CREATE NONCLUSTERED INDEX [IX_LegacyExtract] ON [dbo].[AcmeWidgetTable]
(
    [LegacyExtract] ASC
)