Q:

How Scrapy write CSV files in several times

I"m using scrapy with python 2.7.9 , my spider can crawl the data normally.
But I found the data is too big,so I want to crawl the data in one spider in several times and write to different CSV files. 
For example: Totally ,I have "One hundred and ten thousand " webpages,I want the spider to crawl "30 thousand","30 thousand","30 thousand","20 thousand" respectively.
How can I do? Can I done it only in "spider"? Or maybe in "pipelines" ?
Please somebody help me. 
My code link:https://drive.google.com/open?id=0B6SUWnrBmDwSWmY1em1vbktyOWc&authuser=0

A:

one easy way would be to send from and to as spider arguments
scrapy crawl myspider -a from=30001 -a to=60000

