The query optimizer USES the SYSSTAT catalog views in the database to retrieve the statistical information of the database objects and determine the best way to access the data.
In addition to the easy-to-read formatting, you also have access to annotation that provides critical statistical information to facilitate your analysis of SQL performance.
除了方便阅读格式化，您还可以访问提供了关键统计信息的注释以便于您的SQL性能的分析。
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On a negative note, you discovered that PHP has no native access to sampling distributions, which is a requirement for implementing most statistical tests.