Learn pre-flight checks with practical SQL Server examples, clear checks, and the limits you need before changing application data.
Interview Question of the Week #027 – Move TempDB from One Drive to Another Drive When Low Disk Space
Diagnose low disk pressure in tempdb before moving files, inspect transaction and allocation usage, and plan a verified Windows restart.
Forced Parameterization: When It Cuts CPU and When It Hurts
Test forced parameterization against ad hoc compile pressure with query_hash counts, compilations per second, CPU, and parameter sensitivity.
Reads per Execution: Ranking Queries by Average I/O
The query with the most total reads is not always the one to tune first. Here is how to rank by cost per call and read the spread.
Top N per Group: Three Ways and Which Is Fastest
Compare top N per group with ROW_NUMBER, APPLY and a correlated subquery, define tie behavior, and measure plans with a supporting index.
Cost Threshold for Parallelism and MAXDOP: Setting Both Together
Review cost threshold for parallelism with MAXDOP, inspect NUMA layout and settings, then measure plans and waits after changes.
Physical Reads per Query: Finding What Drives Disk I/O
The storage team asks which query hit the disks. Here is how to answer with physical reads, and why the answer depends on how you rank them.