Reading Showplans

The showplan provides insight about how SQL Server is going to process a SQL statement. If you know what to look for in a showplan, the information it provides can be useful for tuning queries.

Those new to SQL Server should not be dismayed by the jargon used in the showplan. For example, the showplan uses words such as STREAM AGGREGATE. This is just a fancy way of saying that the query contains an aggregate function, such as AVG(), COUNT(), MAX(), MIN(), or SUM(). After you get past the lingo used by the showplan, you will find it a useful tool for optimizing queries.

Instead of looking at every possible output from the showplan, look for table scans in the showplan on tables that contain a large number of records. (Note: It ...

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