为什么查询优化器将小数用作估计的行数？
[英]Why does the query optimizer use decimals for estimated number of rows?
问题描述
I'm analyzing a bad performing query. 
我正在分析性能不佳的查询。 I've looked for an Index Seek node which is generating a high IO. 我一直在寻找产生高IO的Index Seek节点。 I'm assuming this is due to usage of low cardinality index, because estimated number of rows is far from the actual number of returned rows. 我假设这是由于使用了低基数索引，因为估计的行数与返回的实际行数相差甚远。 My question is why the Query Optimizer shows the estimated number of rows in decimal notation such as 2216,86 ? 我的问题是，为什么查询优化器以十进制表示形式（例如2216,86）显示估计的行数？
1 个解决方案
解决方案1
0 2014-03-02 14:52:41
因为可能它内部使用了浮点数进行所有计算？
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