But who stores the metadata for the last date the site updated so you know if it needs to be refetched or not.
We do. First off we have a public parquet-format index of all of the urls we crawl every month. And then that also lives in a HDFS table that determines when we want to recrawl a page we've crawled before.
We do. First off we have a public parquet-format index of all of the urls we crawl every month. And then that also lives in a HDFS table that determines when we want to recrawl a page we've crawled before.