Find which statistics a query used through OptimizerStatsUsage in actual-plan XML, cached plans, and Query Store history.
Temp Table Statistics: Why a #Table Plan Goes Stale
Inspect temp table statistics across procedure calls, compare estimates with loaded rows, and test targeted refresh and recompile fixes.
OPTIMIZED_SP_EXECUTESQL in SQL Server 2025: Fewer Compile Storms
Test OPTIMIZED_SP_EXECUTESQL in SQL Server 2025, inspect compilation counters and cached plans, and compare a concurrent workload.
Estimated vs Actual Rows: The First Thing to Read in a Plan
Read estimated vs actual rows in execution plans, find where the first gap appears, and investigate statistics, parameters, and predicates.
Sample Databases for Practicing Performance Tuning
Use sample databases for practicing performance tuning by checking data volume and skew, then enlarging the right tables carefully.
What Is tempdb, and Why Everyone Shares It
tempdb is one scratch database shared by every database on the instance. The three kinds of thing that land in it, why it is rebuilt at every restart, and the reason its file count keeps coming up.
The Last Actual Execution Plan: LAST_QUERY_PLAN_STATS in Practice
Capture the last actual execution plan with LAST_QUERY_PLAN_STATS, inspect runtime rows, and understand what cache retention cannot provide.