Optimizer dynamic sampling

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Optimizer dynamic sampling refers to the ability of the SQL optimizer to take a sample of rows from a table to calculate missing statistics. Dynamic sampling can be controlled with the OPTIMIZER_DYNAMIC_SAMPLING parameter or the DYNAMIC_SAMPLING hint.

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Dynamic sampling levels

Some of the sampling levels that can be used;

  • level 0 - do not use dynamic sampling
  • level 1 - ???
  • level 2 - ???
  • level 10 - sample all blocks in the table
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External links

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