Unfortunately, such estimates did not adequately account for past differences in rates of sedimentation or losses to the total section of strata during episodes of erosion.
不幸的是,这种估测没有充分考虑到过去在侵蚀期间沉积速率或地层总剖面损失的差异。
3
Generate the access plan and see what the optimizer estimates the total cardinality (Number of rows) returned by the query will be.