(1)sort 算子,会显示排序信息 Sort Method代表排序的方法,包括quicksort(快排)和disksort(外排)。快排即内存够用时,所有的排序操作均在内存中完成,外排说明当前可用内存不足,需要下盘。 (2)hashjoin算子 Buckets:代表hash表中实际使用的桶的个数 Batches:代表hashjoin中实际分块的数量。如果Batches=1,则说明所有...
这个filesort是说, MySQL要多做一次额外的排序, 确切的说是快速排序(Quicksort). 先初步了解下Quicksort排序的概念(From Wikipedia). Quicksort is a divide and conquer algorithm. Quicksort first divides a large array into two smaller sub-arrays: the low elements and the high elements. Quicksort can ...
Filtered measures - filtered measures are visual level calculations with a specific filter applied (for example,Total Sales for France) and are used on some of the visuals created by the insights feature Categorical columns on X-axis unless it defines a sort by column that's scalar. If using...
Photo: Although engineers have tried powering cars with Stirling engines, the experiments weren't that successful. It takes time for a Stirling engine to build up speed and it doesn't handle stopping and starting that well, which makes it less suitable for powering a car than an ordinary inte...
In factories, for example, it's often necessary to lift things only small distances but move them anywhere on the factory floor. If that's a routine part of the production process, the factory probably has an overhead crane with a trolley-mounted hoist that can travel along bridge-like ...
suitable notification is passed. Add to that maybe some skyward-facing camera(s) with one degree or other of image-processing applied to their images to (for example) identify when a particularly nice sunset is happening with plenty of rose-tinted clouds. With enough foresight (and the right ...
But there's surely been a space probe or two with a suitable imager been tasked towards such a shot whilst off mostly perpendicular to the Earth-Moon and a decent distance away to get both in the same shot without distortion... 141.101.98.67 17:52, 22 April 2015 (UTC) I don't agree...
When you apply a decorator to a function, the decorator creates a new function that wraps the original function with some additional behavior. The resulting wrapped function can then be called just like the original function, but with the added behavior provided by the decorator. For example, co...
‘People describe Xerox as a family and I was amazed at the number of people who have worked here for so long.’ It’s tempting to take Moloney’s comments with a pinch of salt, especially considering that when you’ve been working somewhere for only two years, as she has at Xerox, ...
An example, Dodge has some of the worst headlights on new to three year old trucks and SUVs, their cars are low so not too terrible but bad. Chevy and GMC trucks the last two years are terrible. Ford trucks are so tall as to blind people even...