The optimizer can then compare the input variable values to catalog statistics and compute a better selectivity estimate for predicates.
然后,优化器可以将输入变量的值与编目统计进行比较,并为谓词计算出一个更好的选择估计。
Often this is the case because the input data that a particular estimation method requires may be unavailable or inaccurate at the time when an estimate is needed.
这通常是因为在需要评估时,评估方法需要的特定的输入数据可能不可用,或者精度不够。
If your time estimate is not in the drop-down menu, choose More, and to get a small input screen where you can enter your estimate.
如果您的时间估计值没有出现在下拉菜单中,那么您可以选择More,就可以得到一个小的输入界面,您可以在里面输入您的估计值。
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