What is estimated I/O cost, what is estimated CPU cost, and why do these costs in an execution plan have no unit? I answer these common training questions.
SQL SERVER – Fix: Error: 262 : SHOWPLAN permission denied in database
My students got Msg 262, SHOWPLAN permission denied, when they tried to view an execution plan. One GRANT SHOWPLAN statement fixes it.
Finding the Slowest Statement Inside a Stored Procedure
Find the slowest statement inside a stored procedure using query stats offsets, CPU and read totals, then confirm with Query Store.
Finding Single-Use Plans Wasting Memory in the Cache
Find single-use plans, compare their cache memory with the total, and inspect parameterization before discussing server-wide cache settings.
Adaptive Joins: When the Plan Picks Its Join at Run Time
Understand adaptive joins in SQL Server, read their runtime threshold, inspect the actual choice, and test a query hint safely.
Operator Cost Percentages Are Estimates: Read Actual Time Instead
Read operator cost percentages as estimates, then use actual rows, elapsed time, IO, and repeated work to find the real bottleneck.
Rolling Date Ranges Forward Without Hard-Coded Years
Replace hard-coded years with indexed date ranges for current periods, full months, year-to-date comparisons, and any requested year.