Yesterday I delivered a session named ''Developing T-SQL to survive concurrency'' at East Iowa SQL Saturday. Thanks to everyone who attended, and thanks to Michelle Ufford, Chris Leonard, Ed Leighton-Dick, and other volunteers, who organized the event. As promised, here are the links with more information and more repro scripts, more or less in ...

Selects under READ COMMITTED may return incorrect results if the data they select is being modified at the same time. I will provide a repro script which on my laptop returns incorrect results in more than 90% cases. Also I will provide a similar repro script which runs under REPEATABLE READ but still returns incorrect results in more than ...

I have already described several deadlock scenarios that involve only one table in another post. This time I will describe an intermittent deadlock which occurs in high concurrency environments. Before providing a complex repro script for it, I will provide two simpler repro scripts for similar deadlock scenarios (similar deadlock graphs), ...