Since we are not manipulating locks ourselves, the engine is locking each row (or page) as it needs it.
由于我们没有操控锁，因此引擎在需要一行(或者页)时会对其进行锁定。
2
As a result, the engine needed to read many rows of data and apply the final filters using the actual row data, even though indexes of the filter columns were available.
结果，该引擎必须读取很多数据行然后使用实际行数据应用最终过滤，即使过滤列的索引可用。
3
How can you not love a two-door wagon that seats seven (a third row folded up from the floor) and has a two-stroke, three-cylinder engine?