Apache Nutch 2.1 different batch id (null)

Question

I crawl few sites with Apache Nutch 2.1.

While crawling I see the following message on lot of pages:
ex. Skipping http://www.domainname.com/news/subcategory/111111/index.html; different batch id (null).

What causes this error ?
How can I resolve this problem, because the pages with different batch id (null) are not stored in database.

The site that I crawled is based on drupal, but i have tried on many others non drupal sites.

Answer 1

I think, the message is not problem. batch_id not assigned to all of url. So, if batch_id is null , skip url. Generate url when batch_id assined for url.