SQL Server Seek vs Scan: Why a Flat Read Count Lies
A flat read count can hide an index sliding from seeks to scans. Here is how the SQL Server seek vs scan ratio exposes it before queries slow down.
Day: October 7, 2026
SQL Code Smells: Unindexed Range Predicates
When a query filters a large table on a range, like a date window, and no index supports that range, SQL Server scans the table. Put that scan inside a subquery that gets joined to other inputs, and a query that should take seconds can run for hours. In a recent case, one covering index took a query from almost two hours in the worst case down to about four seconds. What is an unindexed range predicate? A range predicate …