[NUTCH-1679] UpdateDb using batchId, link may override crawled page.

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 2.2.1
• Fix Version/s: 2.3.1
• Patch Info: Patch Available
• Assignee: Lewis John McGibbney
• Reporter: Tien Nguyen Manh
• Created: 04/Dec/13 16:27
• Updated: 13/Mar/24 14:50
• Resolved: 16/Sep/15 04:23

Description

The problem is in Hbase store, not sure about other store.

Suppose at first crawl cycle we crawl link A, then get an outlink B.
In second cycle we crawl link B which also has a link point to A
In second updatedb we load only page B from store, and will add A as new link because it doesn't know A already exist in store and will override A.

UpdateDb must be run without batchId or we must set additionsAllowed=false

Here are code for new page
page = new WebPage();
schedule.initializeSchedule(url, page);
page.setStatus(CrawlStatus.STATUS_UNFETCHED);
try

{ scoringFilters.initialScore(url, page); }

catch (ScoringFilterException e)

{ page.setScore(0.0f); }

new page will override old page status, score, fetchTime, fetchInterval, retries, metadata[CASH_KEY]

• i think we can change something here so that new page will only update one column for example 'link' and if it is really a new page, we can initialize all above fields in generator
• or we add operator checkAndPut to store so when add new page we will check if already exist first

Issue Links

• is related to: NUTCH-1922 DbUpdater overwrites fetch status for URLs from previous batches, causes repeated re-fetches
• is related to: GORA-411 Add exists(key) to DataStore interface
• is related to: NUTCH-1556 enabling updatedb to accept batchId