Performance impact of having gaps in Identity Column in SQL Server 2005 We have a number of tables in our database with an identity column as the primary key &amp; clustered index. Over the years records have been added and deleted from these tables and of course there are now gaps in the primary key column.

Is there any impact to the performance of the clustered index on these tables as a result of these "missing" identities?

From my understanding as long as the index b-tree is refreshed then there shouldn't be any problems, but I can't find anything specific to confirm this.

Thanks
I don't see how gaps in your identity values could have A N Y negative impact on your performance.

After all - the values are still all 4-byte integer, they're still as optimal for JOINs as anything can be ..... and even if you have gaps, the IDENTITY values are ever-increasing....

Of course, if you physically deleted rows from your clustered index, then there will be "holes" in your pages (the "Swiss Cheese" problem :-) ) - but those would be fixed by a nightly database maintenance that you certainly do have in place, don't you??

And even if you do occasionally delete a row from your table, the impact on your index fragmentation will be marginal.