Statistics generated include the following:
1，Table statistics
– Number of rows
– Number of blocks
– Average row length
2，Column statistics
– Number of distinct values (NDV) in column
– Number of nulls in column
– Data distribution (histogram)
3，Index statistics
– Number of leaf blocks
– Levels
– Clustering factor
4，System statistics
– I/O performance and utilization
– CPU performance and utilization[@more@]
1，Table statistics
– Number of rows
– Number of blocks
– Average row length
2，Column statistics
– Number of distinct values (NDV) in column
– Number of nulls in column
– Data distribution (histogram)
3，Index statistics
– Number of leaf blocks
– Levels
– Clustering factor
4，System statistics
– I/O performance and utilization
– CPU performance and utilization[@more@]
1，表中块的数目，索引深度，从ROOT块到它的叶块。这些都是计算的很准确的。
2，ORACLE推荐在使用dbms_stat收集的时候,estimate_percent参数使用auto_sample_size 这个去自动让ORACLE根据服务器情况定义收集比例：
EXECUTE DBMS_STATS.GATHER_SCHEMA_STATS('OE',DBMS_STATS.AUTO_SAMPLE_SIZE);
3，
来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/9925929/viewspace-976970/ ，如需转载，请注明出处，否则将追究法律责任。
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