IO stalls measure how long SQL Server waited for the disk, file by file. This post ranks the files of a demo database by stall time, measures a workload with two snapshots, lists the busiest files of a whole instance, and explains how to pick the one file that belongs on the new drive.
Remove Extra tempdb Files in SQL Server Safely
To remove extra tempdb files, empty each file first with DBCC SHRINKFILE and then remove it with ALTER DATABASE. This post checks the file count and the allocation waits before you start, rehearses both steps on a demo database, shows the tempdb statements with their undo, and explains why emptying can fail.
Runnable Sessions in SQL Server: What to Check Next
Runnable sessions are sessions that have everything they need except a free CPU. This post counts requests by status, checks that SQL Server can see every processor, reads the settings that cap CPU use, and lists the statements waiting in the queue, so a long queue next to a half idle CPU stops being a puzzle.
Windows Power Plan for SQL Server: Use High Performance
The Windows power plan decides how fast the processors run, and an energy saving plan can slow SQL Server without raising any error. This post shows how to check the active plan, how to switch it and undo the change, and how to time the difference with a repeatable T-SQL loop.
Signal Waits: Detect CPU Pressure With Wait Statistics
Signal waits are the part of every wait that a task spends in the queue for a free CPU. This post ranks the wait types by signal time, shows why timer waits ruin the total share, and samples the signal share into a small table so a whole working day can be read interval by interval.
THREADPOOL Waits: When Raising Max Worker Count Helps
THREADPOOL waits mean tasks waited for a worker thread. Five read-only queries separate real thread starvation from blocking and busy CPUs. The post lists five signs and shows how to raise the cap in small steps.
Filtered Statistics: Fixing Estimates for Skewed Data
Use filtered statistics to describe skewed customer values, inspect histograms, and test estimates under literal and parameterized queries.