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Andrew Purtell commented on HBASE-13109: ---------------------------------------- Which user community? HBase is the operative one here. Of which phoenix users are a part, of course. [~lhofhansl] Can this change be implemented without adding the new member to this interface? If yes, we should fix Phoenix compilation issues as an accommodation. If no, well these are private annotated interfaces after all and this is a nice perf gain for HBase users, so as 0.98 RM I'll call it as good to stay. > 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)