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12 Steps to SQL Server Query Performance Tuning

Thomas LaRockTechnical Evangelist and Senior DBA

Confio Software

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Step 1: Tables and Rowcounts

• Are you certain they are tables?– Views– Table valued functions

• Are you certain about the rowcounts?– Agile development

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Step 2: Find All Filters

• Examine WHERE and JOIN clauses– Filtered rowcounts

• Bad signs– No filters– Majority of table returned

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Step 3: Selectivity

• Want to know the size of the actual logical sets we are working with

• Most useful for RIGHT, LEFT, OUTER• When is the predicate applied?

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Step 4: Analyze Query Columns

• Looking for ‘*’ or scalar functions– Performance degraders (and risks)

• CASE, CAST, CONVERT• Sub-queries• SARG-able

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Learn the 12 Step Approach Now

Get the full 12-step approach from Tom LaRock, Senior Confio DBA and MVP, at www.confio.com.