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as is, im not sure this patch has any downsides, maybe 1 extra memory comparison? also we should capture SEEK_NEXT_ROW as well trunk/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java <http://review.cloudera.org/r/781/#comment4197> what about SEEK_NEXT_ROW ??? that could be a big win as well. - Ryan On 2010-09-15 16:20:51, Pranav Khaitan wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > http://review.cloudera.org/r/781/ > ----------------------------------------------------------- > > (Updated 2010-09-15 16:20:51) > > > Review request for hbase, stack, Jonathan Gray, Karthik Ranganathan, and > Kannan Muthukkaruppan. > > > Summary > ------- > > Optimize reads for specific columns by reseeking between scans. Use the > reseek logic to jump directly to next required column rather than reading > current column. > > Big performance gain for queries with sparse columns. Not advantageous for > dense ones. Consider this before comitting. > > Further suggestions/questions are welcome! > > > This addresses bugs HBASE-2450, HBASE-2916 and HBASE-2959. > http://issues.apache.org/jira/browse/HBASE-2450 > http://issues.apache.org/jira/browse/HBASE-2916 > http://issues.apache.org/jira/browse/HBASE-2959 > > > Diffs > ----- > > trunk/src/main/java/org/apache/hadoop/hbase/HConstants.java 990674 > trunk/src/main/java/org/apache/hadoop/hbase/KeyValue.java 990674 > > trunk/src/main/java/org/apache/hadoop/hbase/regionserver/ScanQueryMatcher.java > 990674 > trunk/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java > 990674 > > Diff: http://review.cloudera.org/r/781/diff > > > Testing > ------- > > All existing tests pass and make significant use of this code. > > Added a new test file called TestColumnSeeking along with another patch at > https://review.cloudera.org/r/780/. > > > Thanks, > > Pranav > >
