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Posted to dev@hbase.apache.org by Ryan Rawson <ry...@gmail.com> on 2010/09/16 01:47:43 UTC
Re: Review Request: Reseeking directly to required columns

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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:
> 
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> http://review.cloudera.org/r/781/
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> 
> (Updated 2010-09-15 16:20:51)
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> 
> Review request for hbase, stack, Jonathan Gray, Karthik Ranganathan, and Kannan Muthukkaruppan.
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> 
> Summary
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> 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
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> 
> Diffs
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> 
>   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
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> 
> Testing
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> All existing tests pass and make significant use of this code. 
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> Added a new test file called TestColumnSeeking along with another patch at https://review.cloudera.org/r/780/.
> 
> 
> Thanks,
> 
> Pranav
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>