Ray's playground

摘要： MapReduce is the Uzi of aggregation tools. Everything described with count,　distinct, and group can be done with MapReduce, and more. It is a method of aggregation　that can be easily parallelized acro... 阅读全文

摘要： explain is an incredibly handy tool that will give you lots of information about your　queries. You can run it on any query by tacking it on to a cursor. explain returns a　document, not the cursor itse... 阅读全文

摘要： The main.m file has two jobs. First, it creates a primary autorelease pool for your application.Second, it invokes the application event loop.These two elements provide critical elementsto get your ap... 阅读全文