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 …