匿名用户请问各位;DBMS_STATS.GATHER_TABLE_STATS中granularity的AUTO和ALL什么区别?
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Granularity of statistics to collect (only pertinent if the table is partitioned).
‘ALL’ - Gathers all (subpartition, partition, and global) statistics
‘APPROX_GLOBAL AND PARTITION’ - similar to ‘GLOBAL AND PARTITION’ but in this case the global statistics are aggregated from partition level statistics. This option will aggregate all statistics except the number of distinct values for columns and number of distinct keys of indexes. The existing histograms of the columns at the table level are also aggregated.The aggregation will use only partitions with statistics, so to get accurate global statistics, users should make sure to have statistics for all partitions. Global statistics are gathered if partname is NULL or if the aggregation cannot be performed (for example, if statistics for one of the partitions is missing).
‘AUTO’- Determines the granularity based on the partitioning type. This is the default value.
‘DEFAULT’ - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the ‘GLOBAL AND PARTITION’ for this functionality. Note that the default value is now ‘AUTO’.
‘GLOBAL’ - Gathers global statistics
‘GLOBAL AND PARTITION’ - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.
'PARTITION '- Gathers partition-level statistics
‘SUBPARTITION’ - Gathers subpartition-level statistics.
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