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Tag Archives: Statistics

Skewed Data – Poor Cardinality Estimates… and Plans Gone Bad

Sul canale SQLPASS TV √® stata pubblicata la sessione “Skewed Data, Poor Cardinality Estimates, and Plans Gone Bad” tenuta da Kimberly Tripp (@KimberlyLTripp) durante lo scorso PASS Summit 2013. Abstract When data distribution is heavily skewed, cardinality estimation (how many rows the query optimizer expects each operator to process) can be wildly incorrect, resulting in poor quality query plans and …

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