Your SQL Server may be slow for a peculiar reason: a run-away query that pushes-out all other queries from the plan cache, like a huge wave. So called “tsunami query”. Tsunami query wipes other plans from the cache and makes your SQL running slow. Creating tsunami query is easy and usually not intentional: a developer concatenates values in SQL command string. As it “works on my machine”, it easily slips to production (nobody tests for this, right?), and the monster is loose!
Introduction You might have lot of virtual machines (VM) for Dev and Test environments. And a storage with huge amount of space to fit all databases. What are the options? Probably the best for performance would be to connect to…
Introduction Docker is perfect for launching DEV and TEST SQL Server environments, when you need many independent SQL instances, or ability to run and stop instances in seconds, only when you need them. Launched from one common image (1GB in…
Introduction You developed a new TSQL code and want to check is there a slow SQL statement inside and which is it? Or you debug the code and want to know which statement throws error, maybe inside of a trigger…
Do you use ROWVERSION/TIMESTAMP to pull changed data? If you do, you might experience a problem – not all changed rows are pulled, some are skipped. How can that be, if we pulled entire range of rowverion changes with no…
There is often confusion between Login and User in SQL Server. What is the difference and what is the link? I hope to clear that out in this short video:
In a few days I am traveling to Iceland for the first time in life. A land of lava, ice caves and Aurora Borealis. There is a SQL Saturday conference organized by local SQL community that I am looking forward…
Introduction Server is sometimes slow and you want to know why? Here is a lightweight performance logging kit which will give you the answer. It supports SQL Server and SQL Azure Databases, but perfmon part can be used on any…
Introduction Demonstration of the smallest possible deadlock: only one statement, one table, one row. Without transactions (no BEGIN TRANSACTION). Even RCSI (Read Committed Snapshot Isolation) is turned ON to eliminate shared locks. Everything is “by the book” as Books Online…
It is SQL Server user group in Basel, after spending short time in Zürich. I am very happy to meet people there. Presentation will be very useful and interesting, and you are more than welcome to register and get there!
