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• innodb_stats_persistent_sample_pages 

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The number of index pages to sample when estimating cardinality and other statistics for an indexed column, such as those calculated by ANALYZE TABLE . Increasing the value improves the accuracy of index statistics, which can improve the query execution plan, at the expense of increased I/O during the execution of ANALYZE TABLE  for an InnoDB  table. For more information, see Section 15.8.10.1, “Configuring Persistent Optimizer Statistics Parameters” . 

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## Note 

Setting a high value for innodb_stats_persistent_sample_pages  could result in lengthy ANALYZE TABLE  execution time. To estimate the number of database pages accessed by ANALYZE TABLE , see Section 15.8.10.3, “Estimating ANALYZE TABLE Complexity for InnoDB Tables” . 

innodb_stats_persistent_sample_pages  only applies when innodb_stats_persistent is enabled for a table; when innodb_stats_persistent  is disabled, innodb_stats_transient_sample_pages  applies instead. 

• innodb_stats_transient_sample_pages 

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The number of index pages to sample when estimating cardinality and other statistics for an indexed column, such as those calculated by ANALYZE TABLE . The default value is 8. Increasing the value improves the accuracy of index statistics, which can improve the query execution plan, at the expense of increased I/O when opening an InnoDB  table or recalculating statistics. For more information, see Section 15.8.10.2, “Configuring Non-Persistent Optimizer Statistics Parameters” . 

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## Note 

Setting a high value for innodb_stats_transient_sample_pages  could result in lengthy ANALYZE TABLE  execution time. To estimate the number 

