Delete qualified rows from multiple tables with as few logical reads as you can. This puzzle gives a setup script for three small tables, the two rules for the delete and a starting script that costs 19 logical reads. Your task is to beat that number and stay correct.
Trivial Plan: Why Some Queries Skip Full Optimization
Identify a trivial plan in SSMS and cached XML, understand skipped optimizer work, and compare a more complex query without forcing it.
What is Faster, SUM or COUNT? – Interview Question of the Week #231
Question: What is Faster, SUM or COUNT? Answer: Both are the same. I was asked this question during my Comprehensive Database Performance Health Check.
Removing a Bad Plan From Cache Without Clearing Everything
Remove one bad plan from cache by handle, compare narrower recompilation choices, and fix the cause so the plan stays healthy.
Coffee Mug – Indexes and SELECT Queries
Sometimes I feel like I have become a kid again. This morning I received a coffee mug with printed quotes of Indexes and SELECT Queries.
How to List All Memory Optimized Tables in SQL Server? – Interview Question of the Week #227
Question: How to List All Memory Optimized Tables in SQL Server? We will see two different scripts here: One for Database and Second for Tables.
Index Slows Down SELECT? What an Unused Index Costs You
An index slows down SELECT queries only in small ways when the plan never reads it. This post measures compile memory with twelve unused indexes, shows the plan change when a related index appears, and counts what every insert and update pays. The real bill arrives on writes.