Uwe Ricken has been working with IT systems since the 90’s. Uwe was the first MCM + MVP in Germany and he also holds the title of Microsoft Certified Master – SQL Server 2008. Uwe has been blogging since 2010 at db-berater.blogspot.de sharing his deep knowledge, and daily experiences of working with Microsoft SQL Server with the community.
When inserting rows into a heap, SQL Server must sometimes update the PFS page which can PFS contention and affect performance. In this article, Uwe Ricken demonstrates how to measure PFS contention.… Read more
Developer shops may decide to use Read Committed Snapshot Isolation (RCSI) to reduce contention, and possibly improve performance, but it is not without its own pitfalls. In this article, Uwe Ricken describes a situation where long running transactions caused a severe performance degradation when RCSI was in use.… Read more
You should stick to using tables in SQL Server, rather than heaps that have no clustered index, unless you have well-considered reasons to choose heaps. However, there are uses for heaps in special circumstances, and it is useful to know what these uses are, and when you should avoid heaps . Uwe Ricken explains, and demonstrates why you'd be unwise to use heaps rather than tables when the data is liable to change.… Read more
When your SQL Server database is set to have its statistics automatically updated, you will probably conclude that, whenever the distribution statistics are out-of-date, they will be updated before the next query is executed against that index or table. Curiously, this isn't always the case. What actually happens is that the statistics only gets updated if needed by the query optimiser to determine an effective query plan.… Read more
Before you deliberately use a heap in SQL Server rather than a table, it is worth understanding why a heap has such different characteristics, and therefore relative benefits and disadvantages. Forward pointers and the Page Free Space page are designed with performance in mind, but only in certain circumstances. Uwe explains why, and how heaps can be used to advantage.… Read more