英语学习2

1.Scale up your datasets enough and all your apps will come undone. What are the typical problems and where do the bottlenecks generally surface?

如果你的数据集扩展到足够大，你所有的应用程序都会崩溃。典型的问题是什么?瓶颈通常出现在哪里?

scale up：扩大

come undone：这里形容程序崩溃

and：在这句话中表示下半句是结果

2.It was already on its way out by the time I got my hands on it, but in its heyday, the early to mid-1980s, it had been used to support access by social scientists to what was unquestionably “big data” at the time: the entire 1980 U.S. Census database.

在我得到它的时候，它已经在走下坡路了，但在它的全盛时期，也就是20世纪80年代早期到中期，它可以支持社会科学家获取在当时来说毫无疑问是“大数据”的数据:整个1980年的美国人口普查数据库

be on one's way out :走下坡路

get one‘s hand on sth:得到

in one's heyday :全盛时期

access to sth :接近sth的机会，对sth的方法【’aikses】

census 人口普查

后面的句子可以分裂为简单句：

 it had been used by social scientists to support access  to  the entire 1980 U.S. Census database.

demographic：人口普查

bulk：批量

3.on larger tables it switched to sorting by grouping columns—a viable, if suboptimal strategy given a few million rows, but a very poor one when facing a billion. 

它转而通过对列进行分组进行排序——这是一种可行的策略，尽管对于几百万行来说不是最优策略，但是当面对10亿行时，这种策略就很糟糕了

4.It’s worth noting, however, that even had the table’s statistics not been known, on a billion rows it would take far less time to do an initial scan and determine the distributions than to embark on a full-table sort.

然而，值得注意的是，即使还不知道表的统计信息，在10亿行中，进行初始扫描并确定分布所花费的时间也要比进行全表排序所花费的时间少得多

（我可能眼瞎了，把noting看成nothing，然后很疑惑明明啥也不值得怎么翻译成值得注意）

 even had the table’s statistics not been known：虚拟语气倒装，到动词有shoud,had,were的时候省略if然后倒装

embark on：着手，从事

distribution:分布

blink at:对...表示惊讶