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Showing posts with label Query Optimizer. Show all posts
Showing posts with label Query Optimizer. Show all posts

Thursday, 29 July 2010

Inside the Optimizer: Constructing a Plan - Part 1

Inside the Optimizer: Constructing a Plan - Part 1

For today’s entry, I thought we might take a look at how the optimizer builds an executable plan using rules. To illustrate the process performed by the optimizer, we will configure it to produce incrementally better plans by progressively applying the necessary rules.

Wednesday, 28 July 2010

The “Segment Top” Query Optimization

The Segment Top Query Optimization

A question that often comes up on the forums is how to get the first or last row from each group of records in a table. This post describes a clever query plan optimisation that SQL Server can use for these types of query.