Query Tuning SQL Server 2019 Part 4: Long Live The Query Tuner

Rumors Of My Demise


Let’s talk about some common hints that people use to fix parameter sniffing:

  • RECOMPILE: Won’t work here to get us a better plan for VoteTypeId 5, because it sucks when the optimizer knows what’s coming
  • OPTIMIZE

Query Tuning SQL Server 2019 Part 3: Who Died And Made You The Optimizer?

Be Yourself


We’ve got a problem, Sam Houston. We’ve got a problem with a query that has some strange issues.

It’s not parameter sniffing, but it sure could feel like it.

  • When the procedure compiles and runs with VoteTypeId 5,

Query Tuning SQL Server 2019 Part 2: Big Databases, Big Ideas

Are We Still Friends?


When I first wrote this demo, I called it dbo.ParameterSniffingMonstrosity.

Because , you know, it’s really terrible.

CREATE OR ALTER PROCEDURE dbo.VoteSniffing( @VoteTypeId INT )
AS
SET XACT_ABORT, NOCOUNT ON;
    BEGIN
        SELECT   ISNULL(v.UserId, 0) AS 

Query Tuning SQL Server 2019 Part 1: Changing Databases

Teeth To Grit


I’ve always had trouble standing still on SQL Server versions, but most companies don’t. Hardly anyone I talk to is on SQL Server 2017, though these days SQL Server 2016 seems more common than SQL Server 2012, …

SQL Server 2019: Index Choice and Batch Mode On Rowstore

A/B Testing


Let’s look at a pretty simple query against the Votes table:

SELECT v.VoteTypeId, 
       MIN(v.CreationDate) AS min_creation_date,
       MAX(v.CreationDate) AS max_creation_date,
       COUNT_BIG(*) AS records
FROM dbo.Votes AS v
GROUP BY v.VoteTypeId
ORDER BY v.VoteTypeId;

There are only two column involved:…

Using Exchange Demand Partitioning to Improve Parallel Query Scalability

One of our SQL Server workloads runs many concurrent parallel queries on a possibly already busy server. Other work occurring on the server can have dramatic effects on parallel query runtimes. One way to improve scalability of parallel query runtimes …