Articles

External Article

SQL Server Prefetch and Query Performance

Prefetching can make a surprising difference to SQL Server query execution times where there is a high incidence of waiting for disk i/o operations, but the benefits come at a cost. Mostly, the Query Optimizer gets it right, but occasionally there are queries that would benefit from tuning.

2012-06-14

4,026 reads

External Article

A first look at SQL Server 2012 Availability Group Wait Statistics

If you are trouble-shooting an AlwaysOn Availability Group topology, a study of the wait statistics will give a pointer to many of the causes of problems. Although several wait types are documented, there is nothing like practical experiment to familiarize yourself with new wait stats, and Joe Sack demonstrates a way of testing the sort of waits generated by an availability group under various circumstances.

2012-06-12

2,331 reads

Blogs

T-SQL Tuesday #202: 100 Hours

By

It’s time for T-SQL Tuesday again and this is a great prompt to start...

Exploring DiskANN: Part 2: PQ, SSDs, caching and beam search

By

How I used AI for this postChatGPT to generate images based on info specifically...

T-SQL Tuesday #202: The Two Outages I Won't Ever Forget

By

My T-SQL Tuesday #202 entry for Marlon Ribunal's invitation on memorable SQL Server outages....

Read the latest Blogs

Forums

Performance Regression After Upgrading from SQL Server 2016 to 2022

By abdalah.mehdoini

Bonjour à tous, La semaine dernière, nous avons effectué une mise à niveau de...

Adding new column with DEFAULT

By Thomas Franz

Comments posted to this topic are about the item Adding new column with DEFAULT

How do I connect to a SQL Server database on my ISP?

By Doctor Who 2

I've got a web application for my side business. I've added a SQL Server...

Visit the forum

Question of the Day

Adding new column with DEFAULT

Which number will the COUNT() return after executing the following statements:

DROP TABLE IF EXISTS #test;
CREATE TABLE #test (id INT)
INSERT INTO #test (id)
SELECT *
  FROM GENERATE_SERIES(1, 3) AS gs
;

ALTER TABLE #test ADD flag BIT CONSTRAINT DF_#test_flag DEFAULT 0;
go
UPDATE #test SET flag = 0 WHERE id = 1
UPDATE #test SET flag = 1 WHERE id = 2

INSERT INTO #test (id) VALUES (4)

SELECT COUNT(*)
  FROM #test AS t
 WHERE flag = 0
 

See possible answers