Best method to update rows with cron job

[stopblackholes]

I want to run a cron job to update rows every minute. Now the table im updating will probably grow very large in size.

 

 

Should i

 

A. Create a second table to store the data that has not been updated then have the cron job  query that table for the data then update the main table with the related key and afterwards delete it from temp table?

 

B. Or create a extra field in the main table that stores a value that says it needs updating or has been updated and query then update?

[fenway]

That's a bit vague...