Month: April 2019

Join me for a PASS Summit Pre-Con

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I am very excited to announce I will be delivering a pre-conference session on SQL Server Performance Tuning on November 5th at PASS Summit 2019. If you have ever attended one of my sessions, you know how passionate I am about this particular topic. So, you also know how very excited I am to have this opportunity to spend a full day talking about SQL Server Performance Tuning and Optimization. Performance Tuning is one of my favorite things to do with SQL Server. There is nothing like seeing performance improvements in an environment as your reward for your hard work.… Continue Reading

What is Implicit Conversion?

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Another quick post of simple changes you can make to your code to create more optimal execution plans. This one is on implicit conversions. An implicit conversion is when SQL Server must automatically convert a data type from one type to another when comparing values, moving data or combining values with other values. When these values are converted, during the query process, it adds additional overhead and impacts performance. Here is a great chart by Microsoft that shows you conversions and which will cause an implicit or explicit conversion. In this post I will not go into explicit, just know… Continue Reading

What’s a Key Lookup?

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One of the easiest things to fix when performance tuning queries are Key Lookups or RID Lookups. The key lookup operator occurs when the query optimizer performs an index seek against a specific table and that index does not have all of the columns needed to fulfill the result set. SQL Server is forced to go back to the clustered index using the Primary Key and retrieve the remaining columns it needs to satisfy the request. A RID lookup is the same operation but is performed on a table with no clustered index, otherwise known as a heap.  It uses… Continue Reading