With this option, if no rows have changed, the statistic will not be updated. If one or more rows have changed, the statistic will be updated.
Since the release of SP1 for 2012, this has been my only challenge with Ola’s scripts. In SQL Server 2008R2 SP2 and SQL Server 2012 SP1 they introduced the sys.dm_db_stats_properties DMV, which tracks modifications for each statistic. I have written custom scripts to use this information to determine if stats should be updated, which I’ve talked about here. Jonathan has also modified Ola’s script for a few of our customers to look at sys.dm_db_stats_properties to determine if enough data had changed to update stats, and a long time ago we had emailed Ola to ask if he could include an option to set a threshold. Good news, that option now exists!
Keeping statistics up to date is a nice way of quietly improving performance in a system.