Matt Kangas wrote:
Hi Doug, I've taken a quick look at this tonight to see if I
understand all of the relevant concepts. I think I'm about halfway
there. ;-) But I do have a few questions:

Great!

  - iterate through fetcher/ data, generating a <url,segment,n> output
file, where n is the url's position within the segment.
  - sort this file by url.


Would there be value in doing this on a per-segment basis instead of
multi-segment? E.g. creating an output file <url,n> within the segment
directory.

Processing everything at once is optimal in terms of CPU and io, but requires more temporary disk space. So, if disk space is tight then segment-at-a-time might be preferable.


  - merge the sorted file with the db, generating a
<segment,n,inlinks,scores> file.
  - sort this file by <segment,n>.


<inlinks,scores> comes from the webdb, right?

Right. Inlinks are really just anchors. (Finding the incoming url is considerably more expensive, and isn't required.)


  - merge this with the segment's fetcher/ files, rewriting each with
updated inlinks and score.

I'm a bit fuzzy on this one. Where are inlinks and score stored in a segment? FetchListEntry.anchors and FetchList.page.score/nextScore?

Yup. nextScore is only used internally in link-analysis, so all that you need to update is the anchors and score.


Doug


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