Today I want to talk about a specific kind of index in SQL Server: Filtered Indexes, which were introduced back with SQL Server 2008 – so already very long time ago. A Filtered Index is a traditional Non-Clustered Index, which includes a Filter Predicate that restricts the rows that are indexes in that specific index. …
Years ago I wrote about how SQL Server stores VARCHAR columns in the Navigation Structure of an index. As you might know, the key columns of an index in SQL Server (Clustered Index, Non-Clustered Index) have a size limitation of a maximum of 900 bytes. Imagine now that you want to fool SQL Server, and …
Last week I taught an internal SQL Server Performance Tuning course to a customer in Switzerland. As usual we had a lot of fun, and at some point an attendee asked me one of the best questions of my life: “Can you disable a Clustered Index?” At first I was really scared about that question, …
Disabling Clustered Indexes in SQL Server – a really good idea? + read more
In the last weblog post I have talked about the differences in unique and non-unique non-clustered indexes on a unique clustered index. In this weblog post I want to talk about the differences of non-clustered indexes defined on a non-unique clustered index. As you already know from this posting, SQL Server handles non-unique clustered indexes …
Unique and non-unique non-clustered indexes on a non-unique clustered index + read more
In the last weblog post I have talked about the difference of unique and non-unique clustered indexes. As you have seen SQL Server uses an internal overhead of 4 bytes (the so-called uniquifier) to make non-unique clustered index rows unique. Today I want to work out the difference between unique and non-unique non-clustered indexes defined …
Unique and non-unique non-clustered indexes on a unique clustered index + read more
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