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Jonathan Lawlor commented on HBASE-13109: ----------------------------------------- Looks like this introduced some new javadoc warnings that are being called out in other precommit build checks: {quote} [WARNING] /home/jenkins/jenkins-slave/workspace/PreCommit-HBASE-Build/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ExplicitColumnTracker.java:82: warning - @param argument "lookAhead" is not a parameter name. [WARNING] /home/jenkins/jenkins-slave/workspace/PreCommit-HBASE-Build/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ScanQueryMatcher.java:587: warning - @param argument "off" is not a parameter name. [WARNING] /home/jenkins/jenkins-slave/workspace/PreCommit-HBASE-Build/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ScanQueryMatcher.java:587: warning - @param argument "len" is not a parameter name. [WARNING] /home/jenkins/jenkins-slave/workspace/PreCommit-HBASE-Build/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ScanQueryMatcher.java:602: warning - @param argument "off" is not a parameter name. [WARNING] /home/jenkins/jenkins-slave/workspace/PreCommit-HBASE-Build/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ScanQueryMatcher.java:602: warning - @param argument "len" is not a parameter name. {quote} > 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)