Column order matters in Clustered Indexes

Sun, 23 Mar 2025 00:00:00 +0000

Demo scripts below.

I recently worked on a problem for a customer who experienced some performance issues with a job on their SQL Server database.

Because they use SQL Server Standard Edition, their solution included a home-rolled version of table partitioning, where two tables were created every week:

one contained 10-second aggregate values, written in microbatches every 10 seconds
the other similarly contained 5-minute values, written from the 10 second table every 5 minutes

All of these aggregates were based on raw measurements from their various systems, one measurement per device.

Index Tuning on Morten Ankerstjerne

Column order matters in Clustered Indexes