From the course: Learning SQL Server Development on Linux

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Interleaved execution

Interleaved execution

From the course: Learning SQL Server Development on Linux

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Interleaved execution

- [Instructor] So the final of the three SQL Server 2017 Optimizer Enhancements we're going to talk about is Interleaved execution. And why we're talking about this is because SQL Server has traditionally used unidirectional, we'll call it pipe, for optimizing executing queries, so as your query gets optimized and an execution plan gets generated, the cardinality estimator provides row counts in order from right to left in your query to derive its estimated cost. And those determine which plans get selected in execution, and if they're incorrect, SQL Server will still end up using the plan despite the poor original assumptions. And there are some other assumptions that the query optimizer makes, particularly around the object we're going to talk about today, multi-statement table-valued functions. While many DBAs are aware of how bad multi-statement table-valued functions are, they're still widely used, especially in a lot of ISV or independent software vendor applications, and they…

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