> Hi, > > Just a related question: Does.it make a big difference to fetch and parse > directly than fetch all first, then parse. I was.under the impression that > they yield.to the same end result...> .
Yes they produce the same output. > > Remi > > On Wednesday, February 15, 2012, Markus Jelsma <[email protected]> wrote: > >> my questions/doubts are inline > >> > >> On Tue, Feb 14, 2012 at 4:06 PM, Lewis John Mcgibbney < > >> > >> [email protected]> wrote: > >> > Hi Puneet, > >> > > >> > On Tue, Feb 14, 2012 at 5:12 AM, Puneet Pandey <[email protected]> > >> > > >> > wrote: > >> > > I have started using nutch recently. > >> > > As I understand nutch crawling is a cyclic process > >> > > inject->generate->fetch->parse->update > >> > > >> > Yes this is typically what you would execute. > >> > > >> > > 1. When does parse start when I use the "crawl" command line. Is it > >> > > after all the urls have been fetched in the segment? > >> > > >> > Depends on what settings you specify in nutch-site.xml, by default > >> > parsing is done as a separate process (after fetching) when using the > >> > crawl command. > >> > >> Suppose i submitted 10K urls in a segment for crawl. Does the parsing of > >> the content start as soon as the first URL is available (i.e. fetched) > >> or the parsing starts only after all 10K have been fetched. For my use > >> case > > i > > >> want parsing to start on the urls as soon as they are available w/o > > waiting > > >> for fetch on others to complete. > > > > don't use the crawl command, it has fetchign and parsing as separate > > jobs. You > > > need to enable fetcher.parse to parse fetched files immediately. > > > >> > > What if I want to the parse > >> > > the content as soon as it has been fetched? > >> > > >> > Change your settings in nutch-site.xml to override the defaults, then > >> > rebuild the project. > >> > > >> > > 2. Is it possible to run two fetches in parallel? Suppose I generate > > 2 > > >> > > segments is it possible to run fetch on seg1 and seg2 in parallel? > >> > > >> > Yes this is possible, you would set the number of threads in your > > fetcher > > >> > to run this task in parallel. > >> > > >> > I need to crawl 100K urls everyday. I have separate process which > >> > produces > >> > >> the urls for me, but it is a bit time taking process. I do not want to > > wait > > >> for all the urls to be generated and then start the nutch crawl. What i > >> want is to start the nutch fetch process whenever I have received a > >> batch of urls (say 10K) available. Is it possible to inject the batch2 > >> of 10K urls while fetch for batch1 is still running? If yes, when will > >> nutch > > pick > > >> the next batch for crawl. > > > > This is only possible when you use the freegen command. Also, i'd not > > recommend running concurrent jobs in local mode. > > > >> Also, I do not want to crawl any of the links from the fetched pages. > >> The only urls that need to be crawled are the ones generated by my > >> process. > > How > > >> do i ensure this. Is there any config setting with which we can disable > >> crawl of links present in fetched pages? > > > > Update the crawldb with additions disabled. > > > >> > > 3. Can I limit the number of urls per host per segment in the > > generate > > >> > step > >> > > >> > > itself? > >> > > >> > Yes, please check out nutch-default.xml for generator properties, I > > don't > > >> > have the settings off my head but this is possible. > >> > > >> > > Puneet > >> > > >> > -- > >> > *Lewis*
