While working on working on a Comprehensive Database Performance Health Check my client asked me – Do MAX(col) Scan Table? Let us learn about that today.
Are Not Equal to Operators Equal to Not In? – SQL in Sixty Seconds #102
What I love most about my job, is that I get to work with different people and answer questions. Are Not Equal to Operators Equal to Not In?
Compute Scalar Operators: Why a Computed Column Shows Two
A plan that reads a computed column shows two Compute Scalar operators, and the second one looks like a mistake. This post compares three tables in the plan text: an expression in the query, a computed column and a persisted computed column. It shows what each of the Compute Scalar operators defines and whether the extra operator costs anything.
SQL SERVER – Stream Aggregate and Hash Aggregate
Recently during the on-demand consultation, I was asked a very interesting question about Stream Aggregate and Hash Aggregate.
Operator Costs in an Execution Plan: Read Them Without Being Fooled
Interpret operator costs as estimates, compare actual rows and runtime evidence, and find expensive work without trusting plan percentages.
Do Stream Aggregate Operator Always Need Sort Operator? – Interview Question of the Week #240
Question: Do Stream Aggregate Operator Always Need Sort Operator?
Answer: Absolutely No.Before I explain this question a bit more in detail.
SQL SERVER – Is Stream Aggregate is Same as Gather Streams of Parallelism?
Is Stream Aggregate is Same as Gather Streams of Parallelism? – This was one of the brilliant questions I had received during my recent engagement.