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Lars Hofhansl edited comment on HBASE-5121 at 7/22/12 7:07 PM: --------------------------------------------------------------- @chunhui: Could have a look at the suggested change in HBASE-5659? The observation is that: # after the scanner is reset the top KV will in the vast majority of all case be changed # that is only a problem when the top KV's row has changed, in many case StoreScanner.next indicates more work than necessary to a caller. Edit: Misspelled chunhui's name... was (Author: lhofhansl): @chunhiu: Could have a look at the suggested change in HBASE-5659? The observation is that: # after the scanner is reset the top KV will in the vast majority of all case be changed # that is only a problem when the top KV's row has changed, in many case StoreScanner.next indicates more work than necessary to a caller. > MajorCompaction may affect scan's correctness > --------------------------------------------- > > Key: HBASE-5121 > URL: https://issues.apache.org/jira/browse/HBASE-5121 > Project: HBase > Issue Type: Bug > Components: regionserver > Affects Versions: 0.90.4 > Reporter: chunhui shen > Assignee: chunhui shen > Priority: Critical > Fix For: 0.92.1, 0.94.0 > > Attachments: 5121-0.92.txt, 5121-suggest.txt, > 5121-trunk-combined.txt, 5121.90, hbase-5121-testcase.patch, > hbase-5121.patch, hbase-5121v2.patch > > > In our test, there are two families' keyvalue for one row. > But we could find a infrequent problem when doing scan's next if > majorCompaction happens concurrently. > In the client's two continuous doing scan.next(): > 1.First time, scan's next returns the result where family A is null. > 2.Second time, scan's next returns the result where family B is null. > The two next()'s result have the same row. > If there are more families, I think the scenario will be more strange... > We find the reason is that storescanner.peek() is changed after > majorCompaction if there are delete type KeyValue. > This change causes the PriorityQueue<KeyValueScanner> of RegionScanner's heap > is not sure to be sorted. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira