TheSQLGuru (8/7/2014)
I think this is slightly mis-stated Jeff. While you may not get fragmentation from end-of-index inserts, you certainly can get page LATCH contention, which can be a significant bottleneck to good insert performance in such a scenario.
Thanks for the feedback, Kevin. It is certainly possible that I've not worked on a system that has had a high enough level of tail-end inserts to matter. Expedia.com (we took care of the "yellow box" adds at the top and the bottom) was the biggest I've worked on and the number of inserts weren't what I'd call huge (just a couple of hundred every couple of seconds). That's also where the incident with the application timeouts due to page splits on an NCI with low selectivity occurred and that's what I was basing my comment on. It was amazing just how quickly it happend. As soon as the index committed, WHAM! As soon as we dropped the index, the problem went away just as quickly. The table did have a CI on an IDENTITY column.
--Jeff Moden
Change is inevitable... Change for the better is not.