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Posted to issues@kudu.apache.org by "Will Berkeley (JIRA)" <ji...@apache.org> on 2018/05/07 17:11:00 UTC

[jira] [Created] (KUDU-2429) Improve performance of scans on tablets with large blocks of deleted rows

Will Berkeley created KUDU-2429:
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             Summary: Improve performance of scans on tablets with large blocks of deleted rows
                 Key: KUDU-2429
                 URL: https://issues.apache.org/jira/browse/KUDU-2429
             Project: Kudu
          Issue Type: Improvement
          Components: cfile, tablet
    Affects Versions: 1.7.0
            Reporter: Will Berkeley
            Assignee: Todd Lipcon
             Fix For: 1.8.0


Scanning tablets where many of the rows have been deleted is often very slow, since the deletes need to be applied as deltas. It's possible to speed this up in cases where an entire block has been deleted by
1. skipping column materialization for a block if all rows have been deleted
2. skipping reading the selection vector for each column if we know the entire block is deleted and thus contains no results



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