[ http://issues.apache.org/jira/browse/NUTCH-395?page=comments#action_12445532 ] Andrzej Bialecki commented on NUTCH-395: -----------------------------------------
I have several comments to this patch: * have you measured what made the biggest impact on performance - changes to Metadata, or changes to IO in FetcherOutput? * I think it's a good idea to separate two concerns with PlainMetadata / MetadataSpellChecker. Since the latter is a subclass I think it would be more appropriate to name it SpellCheckedMetadata. * I'd also argue for keeping the name Metadata and just replace the body of the class with PlainMetadata implementation - this way we could avoid changing the API in so many places; for compatibility we could just bump the version number in Metadata. We could then avoid also changes to version id-s of other classes that rely on Metadata, such as Content, ParseData et al. * new Metadata / SpellCheckedMetadata need JUnit tests - this is important, because many other classes rely on proper working of these classes. * Fetcher.VoidReducer is not needed - I'm guessing you wanted to use it just for logging. * please observe formatting rules, especially whitespace rules - this patch doesn't follow them. > Increase fetching speed > ----------------------- > > Key: NUTCH-395 > URL: http://issues.apache.org/jira/browse/NUTCH-395 > Project: Nutch > Issue Type: Improvement > Components: fetcher > Affects Versions: 0.8.1 > Reporter: Sami Siren > Assigned To: Sami Siren > Attachments: nutch-0.8-performance.txt > > > There have been some discussion on nutch mailing lists about fetcher being > slow, this patch tried to address that. the patch is just a quich hack and > needs some cleaning up, it also currently applies to 0.8 branch and not trunk > and it has also not been tested in large. What it changes? > Metadata - the original metadata uses spellchecking, new version does not (a > decorator is provided that can do it and it should perhaps be used where http > headers are handled but in most of the cases the functionality is not > required) > Reading/writing various data structures - patch tries to do io more > efficiently see the patch for details. > Initial benchmark: > A small benchmark was done to measure the performance of changes with a > script that basically does the following: > -inject a list of urls into a fresh crawldb > -create fetchlist (10k urls pointing to local filesystem) > -fetch > -updatedb > original code from 0.8-branch: > real 10m51.907s > user 10m9.914s > sys 0m21.285s > after applying the patch > real 4m15.313s > user 3m42.598s > sys 0m18.485s -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
