In this blog post I’ll help you troubleshoot the rare but critical issues of Deadlocked Schedulers and high THREADPOOL waits – using practical means.
Also, very useful T-SQL script towards the end.
Read More »How to Troubleshoot THREADPOOL Waits and Deadlocked Schedulers
This month’s #tsql2sday is hosted by the @AirborneGeek (t|b), who asks us to take a lesson from something frequently done by pilots – learning from accidents and mistakes done by others. As a long-time SQL Server Consultant DBA, I have learned from quite a lot of mistakes done (mostly) by others, seeing as a significant part of my job description is to come over and fix such mistakes. So, today I’ll use this opportunity to talk about one such interesting incident.
Read More »T-SQL Tuesday #128 – Learn from Others
Last week, I called up Matan Yungman, and offered to replace Guy Glantser as a co-host in SQL Server Radio, while Guy is away on holiday in New Zealand.
We recorded episode 111 in English, and episode 117 in Hebrew.
Check them out!
When administrating a SQL Server instance with multiple CPU cores and heavy workload, it’s common to see SQL Server creating and using execution plans with parallelism. The instance configuration “cost threshold for parallelism” is what determines for SQL Server the minimum sub-tree cost before it starts considering to create a parallelism plan. The default “out-of-the-box” value of this configuration is 5.
However, in some cases, we would want to increase the default configuration of “cost threshold for parallelism” to something higher than the Microsoft default of 5, thus decreasing the frequency in which SQL Server creates parallelism plans.
Read More »Planning to Increase Cost Threshold for Parallelism – Like a Smart Person!
Today I’ll talk about the main physical JOIN operator types in SQL Server (Nested Loops, Hash and Merge Joins), their differences, best practices, and complexity (which determines when the SQL Server optimizer would use them in execution plans).
Read More »The LOOP, HASH and MERGE Join Types
Since SQL Server 2005, Microsoft had a nice addition to the common DML statements, UPDATE and DELETE, by allowing the use of the TOP keyword. Well, SQL Server 2019 has just been released, and yet unfortunately for many of us, SQL Server still doesn’t support the use of the TOP keyword in direct combination with the ORDER BY clause. So when we do need to update or delete the top x rows in a table based on a specific order, we’re bound to use all kinds of workarounds.
However, many of the commonly used workarounds are not as efficient as they can be.
Read More »Efficiently UPDATE and DELETE using TOP and ORDER BY
One fateful night, cold and dreary, I’ve stumbled upon how collations can significantly affect performance in SQL Server… Yes, really!
While normalizing a table in their database, one of my clients had weird and inconsistent performance problems and couldn’t find a solution for it for quite a while.
In this post, I will discuss how to remove the IDENTITY property from an existing column using T-SQL (without changing the order of the columns or moving the data into a new table).
Read More »Remove the IDENTITY property from an existing column