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Lars Hofhansl commented on HBASE-13109: --------------------------------------- Pffeeewww... Good. (I admit I am surprised, since the HBase core code would call the new method on the HFileScanner and KeyValueScanner interfaces) The fact remains, though, that we have to get a new version of Phoenix 4.3 and 4.2 out before we ship 0.98.12, else there would be no released version of Phoenix to compile against the current version of 0.98. I discussed offline with [~apurtell], and we think that might the best option. I assume if we can't make that, we'll delay this until 0.98.13. (Sorry for the pain caused here. It's instructive, though, and worth the performance gains) > Make better SEEK vs SKIP decisions during scanning > -------------------------------------------------- > > Key: HBASE-13109 > URL: https://issues.apache.org/jira/browse/HBASE-13109 > Project: HBase > Issue Type: Improvement > Reporter: Lars Hofhansl > Assignee: Lars Hofhansl > Fix For: 2.0.0, 1.0.1, 1.1.0, 0.98.12 > > Attachments: 13109-0.98-v4.txt, 13109-trunk-v2.txt, > 13109-trunk-v3.txt, 13109-trunk-v4.txt, 13109-trunk-v5.txt, 13109-trunk.txt, > nextIndexKVChange_new.patch > > > I'm re-purposing this issue to add a heuristic as to when to SEEK and when to > SKIP Cells. This has come up in various issues, and I think I have a way to > finally fix this now. HBASE-9778, HBASE-12311, and friends are related. > --- Old description --- > This is a continuation of HBASE-9778. > We've seen a scenario of a very slow scan over a region using a timerange > that happens to fall after the ts of any Cell in the region. > Turns out we spend a lot of time seeking. > Tested with a 5 column table, and the scan is 5x faster when the timerange > falls before all Cells' ts. > We can use the lookahead hint introduced in HBASE-9778 to do opportunistic > SKIPing before we actually seek. -- This message was sent by Atlassian JIRA (v6.3.4#6332)