Compare UNION vs UNION ALL through actual plans, duplicate-removal operators, memory grants and reads, then prove when branches cannot overlap.
Bitmap Filters in Parallel Hash Joins: Reading Them in a Plan
Read bitmap filters in parallel hash join plans, compare fact scan output, and distinguish early row rejection from guaranteed savings.
OPTION (FORCE ORDER): When a Join Order Hint Helps and Hurts
Test OPTION (FORCE ORDER) against real join plans, see when fixed table order helps or hurts, and apply a reversible Query Store hint.
An Index Seek That Reads Millions of Rows: Residual Predicates
Diagnose an index seek that reads far more rows than it returns by checking residual predicates, Actual Rows Read and index key order.
Rewriting OR Conditions So the Index Gets Used
Rewrite OR conditions with separate seeks, preserve duplicate and NULL behavior, and compare plans before choosing UNION or recompilation.
Finding Which Statistics a Query Used in the Execution Plan
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.