Web Crawler gets slower with time
We faced the same issue. We resolved this by closing browser automatically after particular time interval. Clear temporary cache and open new browser instance and continue the process.
I am doing a data extraction project where i am required to build a  web scraping program written using python using selenium and phantomjs headless webkit as browser for scaping public information like friendlist in facebook.The program is starting fairly fast but after a day of running it is getting slower and slower and I cannot figure out why ?? Can anyone give me an idea why it is getting slower ? I am running on a local machine which pretty good specs of 4gb ram and quad core processor . Does FB provide any API to find friends of friends ?