A computed column that calls a scalar function can block parallel plans for queries that never read it. Here is how to spot it and test a fix.
Why a Clustered Index Does Not Guarantee Order Without ORDER BY
Explain order without ORDER BY through parallel scans, NOLOCK allocation scans, alternate indexes, shared scans, and the explicit sort fix.
Optimized Plan Forcing: Cutting Compile Time in SQL Server 2022
Check optimized plan forcing in SQL Server 2022 through scoped configuration and Query Store replay flags, then compare compile duration.
Table Partitioning Quiz: When Does It Make a Query Faster?
This Table Partitioning Quiz asks whether a query for last month runs faster once a sales table is partitioned by month. The answer is only when the filter lets SQL Server skip partitions. A tested script shows the partition count, the reads, and a partition SWITCH.
Query Store Quiz: Where Is Last Week’s Slow Query?
This Query Store Quiz starts with a slow query from last week and a plan cache that restarted empty. The answer is Query Store, which keeps plans and run times inside the database. A tested T-SQL script finds the query, its plan and its duration.
Stored Procedure Recompile Quiz: What Forces a New Plan?
This Stored Procedure Recompile Quiz asks which action makes SQL Server build a new plan for a procedure. The answer is a new index on a table it reads. A tested script uses plan counters to show what reuses the plan and what rebuilds it.
Scalar Functions and Performance
Scalar functions can hide row-by-row work in SQL Server; learn when inlining helps, how to inspect eligibility, and when a set-based rewrite wins.