New Course: “SQL Server: Common Performance Issue Patterns”

My latest course, “SQL Server: Common Performance Issue Patterns“  was just published by The course description is as follows: “There are a wealth of problems that can affect the performance of SQL Server workloads, and Joe shows you more than 35 common performance issue patterns. With 17 detailed demos, you’re shown how to recognize each […]

Simple-Talk Article: “Fixing Gatekeeper Row Cardinality Estimate Issues”

I wrote a new article for Simple-Talk that was published recently: Fixing Gatekeeper Row Cardinality Estimate Issues In the article I talk about a specific cardinality estimation issue you may see for relational data warehouse queries (specifically against star schemas) and a few recommended solutions that may help eliminate or at least reduce the overall […] “Ten Common Threats to Execution Plan Quality”

My second guest blog post was published today on Ten Common Threats to Execution Plan Quality This is related to the subject of my recent SQLSaturday presentation and this is a big subject with a real tactical benefit from a performance tuning perspective, so I’ll be expanding it out over time in various formats […]

Distributed Query Plan Quality and SQL Server 2012 SP1

SQL Server 2012 Service Pack 1 is out today and it fixes an issue that has been around for several versions regarding distributed queries and poor quality execution plans due to bad cardinality estimates when the distributed query principal had insufficient permissions to gather the applicable statistics.  The description of this fix can be found […]

Avoid false negatives when comparing sys.dm_io_virtual_file_stats data to perfmon counter data

  A quick and somewhat nuanced tip today… When evaluating sys.dm_io_virtual_file_stats against collected perfmon counter data, be careful not to erroneously invalidate the latency findings by measuring and comparing against the averages of already-averaged collected performance monitor data (e.g. Avg. Disk sec/Write, Avg. Disk sec/Read ).  I’ve seen scenarios where there is true I/O latency […]