[ http://issues.apache.org/jira/browse/NUTCH-395?page=comments#action_12445994 ] Andrzej Bialecki commented on NUTCH-395: -----------------------------------------
> Now that I remember, there was one more odd thing in current implementation: > the max number > of links was not enforced when writing outlinks only when reading them, I am > planning to change > this also so the number of links is enforced on write. AFAIK this was done on purpose, to facilitate processing of existing data created with different settings. I.e. if someone created a segment with high max # of outlinks, you should still be able to read it and process all outlinks. If you enforce the max # during reading you won't be able to process this data. > 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
